Laser apparatus, laser irradiation method, manufacturing method for semiconductor device, semiconductor device, production system for semiconductor device using the laser apparatus, and electronic equipment

ABSTRACT

Provided are a laser apparatus of continuous oscillation that is capable of enhancing the efficiency of substrate processing, a laser irradiation method, and a manufacturing method for a semiconductor device using the laser apparatus. A portion of a semiconductor film that should be left on a substrate after patterning is grasped in accordance with a mask. Then, a portion to be scanned with a laser light is determined so that it is possible to crystallize at least the portion to be obtained through the patterning. Also, a beam spot is made to strike the portion to be scanned. As a result, the semiconductor film is partially crystallized. That is, with the present invention, the laser light is not scanned and irradiated onto the entire surface of a semiconductor film but is scanned so that at least an indispensable portion is crystallized. With the construction described above, it becomes possible to save a time taken to irradiate the laser light onto a portion that will be removed through the patterning after the crystallization of the semiconductor film.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a laser processing apparatus anda laser irradiation method for crystallizing a semiconductor substrate,a semiconductor film or the like using a laser light or for performingactivation after ion implantation, a semiconductor device formed byusing the laser apparatus and a manufacturing method thereof, anelectronic equipment using the semiconductor device, and a productionsystem of the semiconductor device using the laser apparatus.

[0003] 2. Description of the Related Art

[0004] In recent years, a technique of forming a TFT over a substratehas greatly progressed, and its application and development for activematrix semiconductor display device has been advanced. In particular,since a TFT using a polysilicon film has higher field-effect mobilitythan a TFT using a conventional amorphous silicon film, it enables highspeed operation. Therefore, although the pixel is conventionallycontrolled on a driving circuit provided outside the substrate, it ispossible to control the pixel on the driving circuit formed over thesame substrate.

[0005] Incidentally, as the substrate used in the semiconductor device,a glass substrate is regarded as important in comparison with a singlecrystal silicon substrate in terms of the cost. Since a glass substrateis inferior in heat resistance and is susceptible to heat-deformation,in the case where a polysilicon TFT is formed on the glass substrate,laser annealing is used for crystallization of the semiconductor film inorder to avoid heat-deformation of the glass substrate.

[0006] Characteristics of laser annealing are as follows: it can greatlyreduce a processing time in comparison with an annealing method usingradiation heating or conductive heating; and it hardly causes thermaldamage to the substrate by selectively and locally heating asemiconductor or the semiconductor film.

[0007] Note that the laser annealing method here indicates a techniqueof recrystallizing the damaged layer formed over the semiconductorsubstrate or the semiconductor film, and a technique of crystallizingthe amorphous semiconductor film formed on the substrate. Also, thelaser annealing method here includes a technique applied to leveling orsurface reforming of the semiconductor substrate or the semiconductorfilm. A laser oscillation apparatus applied is a gas laser oscillationapparatus represented by an excimer laser or a solid laser oscillationapparatus represented by a YAG laser. It is known as the apparatus whichperforms crystallization by heating a surface layer of the semiconductorby irradiation of the laser light in an extremely short period of timeof about several ten nanoseconds to several hundred microseconds.

[0008] Lasers are roughly divided into two types: pulse oscillation andcontinuous oscillation, according to an oscillation method. In the pulseoscillation laser, an output energy is relatively high, so that massproductivity can be increased assuming the size of a beam spot to beseveral cm² or more. In particular, when the shape of the beam spot isprocessed using an optical system and made to be a linear shape of 10 cmor more in length, it is possible to efficiently perform irradiation ofthe laser light to the substrate and further enhance the massproductivity. Therefore, for crystallization of the semiconductor film,the use of a pulse oscillation laser is becoming mainstream.

[0009] However, in recent years, in crystallization of the semiconductorfilm, it is found that grain size of the crystal formed in thesemiconductor film is larger in the case where the continuousoscillation laser is used than the case where the pulse oscillationlaser is used. When the crystal grain size in the semiconductor filmbecomes large, the mobility of the TFT formed using the semiconductorfilm becomes high and variation of the TFT characteristics due to agrain boundary is suppressed. Therefore, a continuous oscillation laseris recently attracting attention.

[0010] However, since the maximum output energy of the continuousoscillation laser is generally small in comparison with that of thepulse oscillation laser, the size of the beam spot is small, which isabout 10⁻³ mm². Accordingly, in order to treat one large substrate, itis necessary to move a beam irradiation position on the substrate upwardand downward, and right and left, it results in increasing theprocessing time per one substrate. Thus, processing efficiency is poorand it is an important object to improve the processing speed of thesubstrate.

SUMMARY OF THE INVENTION

[0011] The present invention has been made in view of the aboveproblems, and therefore it is an object of the present invention toprovide a continuous oscillation laser apparatus, a laser irradiationmethod, and a method of manufacturing a semiconductor device using thecontinuous oscillation laser apparatus, which can enhance a processingefficiency in comparison with the conventional example.

[0012] The laser apparatus of the present invention includes: a firstmeans for controlling an irradiation position of each laser light on anobject to be processed; a plurality of second means (laser oscillationapparatuses) for oscillating laser lights; a third means (opticalsystem) for having beam spots of the laser lights oscillated from theplurality of laser oscillation apparatuses partially overlap each otheron the object to be processed; and a fourth means for controlling theoscillation by each of the plurality of second means and alsocontrolling the first means so that the beam spots of the laser lightscover a position determined in accordance with data (patterninformation) concerning a shape of a mask.

[0013] It should be noted here that the position determined inaccordance with the mask data means a portion of a semiconductor film tobe obtained by performing patterning after crystallization. With thepresent invention, in accordance with the mask, the fourth means graspsa portion of the semiconductor film formed on an insulating surface thatshould be left on a substrate after the patterning. In addition, aportion to be scanned with the laser lights is determined so that atleast the portion to be obtained by performing the patterning iscrystallized, and the first means is controlled so that the beam spotsstrike the portion to be scanned. In this manner, the semiconductor filmis partially crystallized. That is, with the present invention, thelaser lights are not scanned and irradiated onto the entire surface ofthe semiconductor film but are scanned so that at least an indispensableportion is crystallized. With the construction described above, itbecomes possible to save a time taken to irradiate the laser lights ontoa portion to be removed through the patterning after the crystallizationof the semiconductor film.

[0014] With the present invention, in order to realize the constructiondescribed above, after the formation of the semiconductor film, prior tothe crystallization using the laser lights, a marker is given to thesemiconductor film using a laser light. Then, a position, at which thelaser lights should be scanned, is determined based on a mask withreference to the position of the marker.

[0015] With the construction described above, it becomes possible toshorten a time taken to irradiate the laser lights and also to improve aspeed at which a substrate is processed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In the accompanying drawings:

[0017]FIG. 1 shows a construction of the laser apparatus of the presentinvention;

[0018]FIGS. 2A and 2B show a shape of a laser beam of the presentinvention and distribution of its energy density, respectively;

[0019]FIGS. 3A and 3B show shapes of laser beams of the presentinvention and distribution of their energy densities, respectively;

[0020]FIGS. 4A to 4C show a direction in which laser lights move on anobject to be processed;

[0021]FIGS. 5A and 5B also show the direction in which the laser lightsmove on the object to be processed;

[0022]FIGS. 6A and 6B show a direction in which the laser lights move onan active layer of a TFT;,

[0023]FIGS. 7A and 7B show positions of markers;

[0024]FIG. 8 is a flowchart showing an operation flow of a productionsystem of the present invention;

[0025]FIG. 9 is a flowchart showing an operation flow of a conventionalproduction system;

[0026]FIG. 10 is another flowchart showing the operation flow of theproduction system of the present invention;

[0027]FIGS. 11A and 11B show an optical system of the laser apparatus ofthe present invention;

[0028]FIG. 12 also shows the optical system of the laser apparatus ofthe present invention;

[0029]FIG. 13 shows the direction in which the laser lights move on theobject to be processed;

[0030]FIG. 14 shows the direction in which the laser lights move on theobject to be processed;

[0031]FIG. 15 shows directions in which the laser lights move on theobject to be processed;

[0032]FIGS. 16A and 16B show a construction of markers;

[0033]FIG. 17 shows an optical system of the laser apparatus of thepresent invention;

[0034]FIG. 18 also shows the optical system of the laser apparatus ofthe present invention;

[0035]FIG. 19 also shows the optical system of the laser apparatus ofthe present invention;

[0036]FIG. 20 is an SEM photograph of a crystallized semiconductor film;

[0037]FIG. 21 is an SEM photograph of the crystallized semiconductorfilm;

[0038]FIGS. 22A and 22B show the characteristics of a TFT;

[0039]FIGS. 23A and 23B show the characteristics of the TFT;

[0040]FIGS. 24A to 24H each show electronic equipment that uses thesemiconductor device of the present invention;

[0041]FIGS. 25A to 25C show a manufacturing method for a semiconductordevice that uses the laser apparatus of the present invention;

[0042]FIGS. 26A to 26C show a manufacturing method for the semiconductordevice that uses the laser apparatus of the present invention;

[0043]FIGS. 27A to 27C show a manufacturing method for the semiconductordevice that uses the laser apparatus of the present invention;

[0044]FIG. 28 shows a manufacturing method for the semiconductor devicethat uses the laser apparatus of the present invention;

[0045]FIG. 29 shows a liquid crystal display apparatus manufacturedusing the laser apparatus of the present invention;

[0046]FIGS. 30A and 30B show a manufacturing method for a light-emittingapparatus that uses the laser apparatus of the present invention;

[0047]FIGS. 31A to 31D are each an inverse pole figure of asemiconductor film;

[0048]FIGS. 32A to 32D are each an inverse pole figure of thesemiconductor film;

[0049]FIGS. 33A and 33B show the direction in which the laser lightsmove on the object to be processed;

[0050]FIGS. 34A to 34C show a construction of position control means;

[0051]FIGS. 35A and 35B show a construction of an active vibrationremoving base;

[0052]FIG. 36 shows distribution of energy densities in the center axisdirection of laser beams made to overlap each other;

[0053]FIG. 37 shows a relation between (i) a distance between thecenters of laser beams and (ii) an energy difference; and

[0054]FIG. 38 shows distribution of output energy of a laser beam in thecenter axis direction.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0055] Hereinafter, there will be described a construction of the laserapparatus of the present invention. FIG. 1 is a block diagram of thelaser apparatus of the present invention.

[0056] A laser apparatus 100 of the present invention includes a stagecontroller 101 that corresponds to a first means for controlling anirradiation position of each laser light on an object to be processed.

[0057] Also, the laser apparatus 100 of the present invention includes aplurality of laser oscillation apparatuses 102 (102 a to 102 d) thatcorrespond to a second means for oscillating laser lights. Note that anexample where four laser oscillation apparatuses 102 a to 102 d areprovided is shown in FIG. 1, although the number of the laseroscillation apparatuses 102 possessed by the laser apparatus 100 of thepresent invention is not limited to this. There occurs no problem solong as the number of the laser oscillation apparatuses 102 possessed bythe laser apparatus 100 of the present invention is in a range of fromtwo to eight. Also, all of the laser oscillation apparatuses use thesame laser and it does not matter whether the wavelengths thereof arethe same to each other or are different from each other.

[0058] It is possible to change the laser as appropriate depending onthe purpose of processing. In the present invention, it is possible touse a publicly known laser. As the laser, it is possible to use a gaslaser or solid-state laser of continuous oscillation. As the gas laser,it is possible to cite an excimer laser, an Ar laser, a Kr laser, andthe like. On the other hand, as the solid-state laser, it is possible tocite a YAG laser, a YVO₄ laser, a YLF laser, a YAlO₃ laser, a glasslaser, a ruby laser, an alexandrite laser, a Ti: sapphire laser, a Y₂O₃laser, and the like. As the solid-state laser, there is applied a laserthat uses a crystal such as YAG, YVO₄, YLF, YAlO₃, or the like dopedwith Cr, Nd, Er, Ho, Ce, Co, Ti, Yb, or Tm. The fundamental wave of thelaser differs depending on a material to be doped and there is obtaineda laser light having a fundamental wave in the neighborhood of 1 μm. Itis possible to obtain a harmonic wave with respect to the fundamentalwave using a nonlinear optical element.

[0059] Also, it is further possible to use an ultraviolet laser lightobtained by converting an infrared laser light emitted from asolid-state laser into a green laser light using a nonlinear opticalelement and by further processing the green laser light using anothernonlinear optical element.

[0060] It should be noted here that there occurs no problem even if thelaser apparatus of the present invention is provided with means foradjusting the temperature of the object to be processed in addition tothe four means described above.

[0061] Also, the laser apparatus 100 of the present invention includesan optical system 103 that corresponds to a third means that is capableof having beam spots of laser lights oscillated from respective laseroscillation apparatuses 102 a to 102 d overlap each other on the objectto be processed.

[0062] The laser apparatus 100 of the present invention further includesa CPU 104 that corresponds to a fourth means. The CPU 104 is capable ofcontrolling the oscillation by the laser oscillation apparatuses 102 andalso controlling the stage controller 101 corresponding to the firstmeans so that the beam spots of the laser lights cover positionsdetermined in accordance with data concerning masks.

[0063]FIG. 2A shows an example of the shape of a laser spot of a laserlight oscillated from each of the laser oscillation apparatuses 102 a to102 d on the object to be processed 107. The beam spot shown in FIG. 2Ahas an elliptic shape. Note that in the laser apparatus of the presentinvention, the beam spots of the laser lights oscillated from the laseroscillation apparatuses are not limited to the elliptic shape. Theshapes of the laser spots differ depending on the kind of the laser andit is possible to shape the beam spots with an optical system. Forinstance, the laser light emitted from the XeCl excimer laser (whosewavelength is 308 nm and pulse width is 30 ns) L3308 manufactured byLambda K. K. has a rectangular shape whose size is 10 mm×30 mm (both ofwhich are the half-value width in a beam profile). Also, the laser lightemitted from the YAG laser has a circular shape if a rod has acylindrical shape, and has a rectangular shape if the rod has a slabshape. Also, by further shaping such a laser light with an opticalsystem, it is possible to form a laser light having a desired size.

[0064]FIG. 2B shows distribution of a laser light energy density of thebeam spot shown in FIG. 2A in a major axis y direction. As to thedistribution of the energy density of a laser light whose beam spot hasan elliptic shape, the energy density is increased in accordance withthe reduction of a distance to the center “o” of the ellipse. The rangespecified by “α” corresponds to the width in the major axis y directionwhere the energy density exceeds a value that is necessary to obtain adesired crystal.

[0065] Next, FIG. 3A shows shapes of beam spots in the case where thereare synthesized laser lights that each has the beam spot shown in FIG.2A. As shown in FIG. 3A, the beam spots of respective laser lights arecombined by matching the major axes of respective ellipses and alsohaving the beam spots overlap each other, thereby forming one beam spot.Note that a straight line obtained by connecting the centers “o” ofrespective ellipses will be hereinafter referred to as the “centeraxis”.

[0066]FIG. 3B shows distribution of energy densities of the laser lightsshown in FIG. 3A, whose beam spots have been combined, in the centeraxis direction. There is increased the energy density in each portion inwhich respective beam spots before the synthesizing overlap each other,so that the energy density is flattened in each portion between thecenters “o” of respective ellipses.

[0067] As can be seen from FIG. 3B, by having a plurality of laserlights overlap each other and having the laser lights complement eachother in each portion having a low energy density, it becomes possibleto enhance the crystallinity of a semiconductor film with efficiency incomparison with a case where the plurality of laser lights are not madeto overlap each other and are used independently of each other. Forinstance, it is assumed that there is exceeded a value of the energydensity that is necessary to obtain a desired crystal only in the areaspecified by the sloped lines in FIG. 3B and the energy densities inother areas are low. In this case, if the four beam spots are not madeto overlap each other, the desired crystal is obtained only in thesloped-line area whose width in the center axis direction is indicatedby “α”. However, by having the beam spots overlap each other as shown inFIG. 3B, it becomes possible to obtain the desired crystal in the areawhose width in the center axis direction is indicated by β (β>4α). As aresult, it becomes possible to crystallize a semiconductor film withmore efficiency.

[0068] A case where the object to be processed 107 in FIG. 3A is asemiconductor film formed over a substrate will be described withreference to FIG. 4A. Note that FIG. 4A shows a semiconductor film 500formed in order to manufacture a semiconductor device of active matrixtype. The portion surrounded by a broken line 501 corresponds to aportion in which there is formed a pixel portion, the portion surroundedby a broken line 502 corresponds to a portion in which there is formed asignal line driving circuit, and the portion surrounded by a broken line503 corresponds to a portion in which there is formed a scanning linedriving circuit.

[0069] Also, in the present invention, a plurality of laser lights aresynthesized by having the beam spots thereof overlap each other, therebyforming one beam spot. When doing so, respective beam spots are made tooverlap each other so that the centers of respective beam spots beforethe synthesizing form a straight line.

[0070] It should be noted here that it does not matter whether or notthe beam spot after the synthesizing is set so that a straight line(hereinafter referred to as the “center axis”) formed by connectingcenters of the beam spots before the synthesizing extends perpendicularto a scanning direction. In the case where the center axis of the beamspot after the synthesizing extends perpendicular to the scanningdirection, the efficiency of the processing of a substrate is increasedto the highest level. On the other hand, there are obtained advantagesgiven below by performing the scanning so that the center axis of thebeam spot after the synthesizing and the scanning direction form anangle of 45°±35°, preferably, an angle closer to 45°.

[0071]FIGS. 31A and 31B are each a map diagram of an inverse pole figureconcerning a crystal orientation when crystallization is performedthrough the irradiation of Nd: YVO₄ on a 1000 Å amorphous silicon filmformed on a silicon nitride film by setting the angle of the center axisof the beam spot with respect to the scanning direction at 27°, settingthe wavelength at 532 nm, setting the output energy at 2 W, and settingthe moving speed at 20 cm/sec. When a direction perpendicular to thescanning direction within a plane parallel to the substrate is referredto as “x”, the scanning direction is referred to as “y”, and a directionperpendicular to the substrate is referred to as “z”, FIG. 31A shows thedistribution of the crystal orientation on a plane perpendicular to thez direction of the semiconductor film and FIG. 31B shows thedistribution of the crystal orientation on a plane perpendicular to they direction. Also, FIG. 31C is an inverse pole figure on a planeperpendicular to the y direction and shows the distribution ratiobetween respective crystal orientations. Further, FIG. 31D is a polefigure in which TD corresponds to the scanning direction y, referencenumeral 001 represents a pole figure on a plane perpendicular to the zdirection, reference numeral 011 represents a pole figure on a planeperpendicular to a direction in which there are synthesized the ydirection and the z direction, and reference numeral 111 represents apole figure on a plane perpendicular to a direction in which there aresynthesized the x direction, y direction, and z direction.

[0072]FIGS. 32A and 32B are each a map diagram of an inverse pole figureconcerning a crystal orientation when crystallization is performedthrough the irradiation of Nd: YVO₄ on a 1000 Å amorphous silicon filmformed on a silicon nitride film by setting the angle of the center axisof the beam spot with respect to the scanning direction at 45°, settingthe wavelength at 532 nm, setting the output energy at 1.6 W, andsetting the moving speed at 20 cm/sec. When a direction perpendicular tothe scanning direction within a plane parallel to the substrate isreferred to as “x”, the scanning direction is referred to as “y”, and adirection perpendicular to the substrate is referred to as “z”, FIG. 32Ashows the distribution of the crystal orientation on a planeperpendicular to the z direction of the semiconductor film and FIG. 32Bshows the distribution of the crystal orientation on a planeperpendicular to the y direction. Also, FIG. 32C is an inverse polefigure on a plane perpendicular to the y direction and shows thedistribution ratio between respective crystal orientations. Further,FIG. 32D is a pole figure in which TD corresponds to the scanningdirection y, reference numeral 001 represents a pole figure on a planeperpendicular to the z direction, reference numeral 011 represents apole figure on a plane perpendicular to a direction in which there aresynthesized the y direction and the z direction, and reference numeral111 represents a pole figure on a plane perpendicular to a direction inwhich there are synthesized the x direction, y direction, and zdirection.

[0073] As can be seen from FIGS. 31A to 31D and 32A to 32D, crystalgrains grow in a direction perpendicular to the center axis of the beamspot. With the construction described above, the number of crystalgrains existing in an active layer is increased and it becomes possibleto reduce variations in characteristics resulting from the crystalorientation and crystal grains in comparison with a case where scanningis performed so that the scanning direction and the center axis of thebeam spot become perpendicular to each other.

[0074]FIG. 4B is an enlarged view of a beam spot 507 in the portion 501in which there is formed the pixel portion. Also, FIG. 4C is an enlargedview of the beam spot 507 in the portion in which there is formed thesignal line driving circuit 502. With the present invention, there isprevented a situation where the center axis of the beam spot 507 extendsperpendicular to the scanning direction. In more detail, an acute angleθ _(A) formed between the center axis of the beam spot and the scanningdirection is set so as to be 45°±35° more preferably, 45°.

[0075] In addition, the energy densities of the laser lights in edgeportions of the beam spots are lower than those in other portions asshown in FIG. 3B, and there is a case where it is impossible touniformly perform the processing of the object to be processed.Consequently, it is preferable that the laser lights are irradiated sothat there is prevented a situation where each portion 506 correspondingto an island-like semiconductor film obtained by patterning thesemiconductor film after crystallization overlaps the edges of the pathsof the laser lights.

[0076] It should be noted here that the laser lights are scanned in thearrow direction in FIG. 4A, although it is not necessarily required thatthe scanning is performed in this arrow direction. FIG. 33A shows anexample where the scanning direction of the laser lights is rotated by90° with reference to the case shown in FIG. 4A. Also, FIG. 33B shows anexample where the scanning direction of the laser lights in the pixelportion 501 and the scanning line driving circuit 503 is the same asthat in the case shown in FIG. 33A and laser lights, whose scanningdirection is the same as that in the case shown in FIG. 33A, and a laserlight, whose scanning direction is the same as that in the case shown inFIG. 4A, are both irradiated in the signal line driving circuit 502. Inthis case, the surface of the semiconductor film is placed in a roughstate in each portion in which the laser lights overlap each other, sothat it is preferable that there is prevented a situation where thelaser lights overlap in each portion in which an active layer is to beformed. Also, laser lights having different scanning directions areirradiated in the signal line driving circuit in FIG. 33B, although suchlaser lights having different scanning directions may also be irradiatedin the scanning line driving circuit 503 and the pixel portion 501.

[0077] Also, with the present invention, each portion to be scanned withthe laser lights is determined in accordance with a mask for patterningthe semiconductor film inputted into the CPU 104. Note that the portionto be scanned with the laser lights is set so as to cover a portion ofthe semiconductor film to be obtained through patterning aftercrystallization. The CPU 104 determines the portion to be scanned withthe laser lights so that at least each portion of the semiconductor filmto be obtained by performing patterning can be crystallized, andcontrols the stage controller 101 corresponding to the first means sothat beam spots, that is, irradiation positions strike the portion to bescanned. In this manner, the semiconductor film is partiallycrystallized.

[0078]FIG. 5A shows a relation between each portion to be scanned withthe laser lights and a mask. Note that the center axis of the beam spotsextends almost perpendicular to the scanning direction in FIG. 5A. FIG.5B shows a relation between the portion to be scanned with the laserlights and the mask in the case where the center axis of the beam spotsand the scanning direction form an angle of 45°. Reference numeral 510denotes island-like semiconductor films of the semiconductor film to beobtained by performing patterning, and each portion to be scanned withthe laser lights is determined so as to cover these island-likesemiconductor films 510. Reference numeral 511 indicates the portions tobe scanned with the laser lights that cover the island-likesemiconductor films 510. As shown in FIGS. 5A and 5B, with the presentinvention, the laser lights are not irradiated onto the entire surfaceof the semiconductor film but are scanned so that at least eachindispensable portion is crystallized.

[0079] It should be noted here that in the case where the semiconductorfilm after the crystallization is used as the active layer of a TFT, itis preferable that the scanning direction of the laser lights isdetermined so as to be parallel to the direction in which carriers in achannel formation region move.

[0080]FIGS. 6A and 6B each show an example of the active layer of a TFT.FIG. 6A shows an active layer in which one channel formation region isprovided and impurity regions 521 and 522 that will become a sourceregion and a drain region are provided so that the channel formationregion 520 is sandwiched therebetween. When the semiconductor film iscrystallized using the laser apparatus of the present invention, thescanning direction of the laser lights is determined so that thescanning direction becomes parallel to a direction in which the carriersin the channel formation region move, as indicated by the arrow.Reference numeral 523 indicates the shape of the beam spot. In a region524 of the beam spot 523 specified by sloped lines, the energy densityexceeds the value that is necessary to obtain a favorable crystal. Byhaving the laser light in the region 524 specified by the sloped linesirradiated onto the entire surface of the active layer, it becomespossible to further enhance the crystallinity of the active layer.

[0081] Also, FIG. 6B shows an active layer provided with three channelformation regions. In this drawing, impurity regions 533 and 534 areprovided so that the channel formation region 530 is sandwichedtherebetween. Also, impurity regions 534 and 535 are provided so thatthe channel formation region 531 is sandwiched therebetween. Further,impurity regions 535 and 536 are provided so that the channel formationregion 532 is sandwiched therebetween. In addition, when thesemiconductor film is crystallized using the laser apparatus of thepresent invention, the scanning direction of the laser lights isdetermined so that the scanning direction becomes parallel to thedirection in which carriers in the channel formation regions move, asindicated by the arrow.

[0082] It should be noted here that in order to determine each portionto be scanned with the laser lights, it is necessary that markers fordetermining the positions of masks with respect to the semiconductorfilm are formed in the semiconductor film. FIGS. 7A and 7B each show thepositions at which the markers are formed in a semiconductor film formedin order to produce a semiconductor device of active matrix type. Notethat FIG. 7A shows an example where one semiconductor device ismanufactured from one substrate, while FIG. 7B shows an example wherefour semiconductor devices are manufactured from one substrate.

[0083] In FIG. 7A, reference numeral 540 denotes a semiconductor filmformed on a substrate, the portion surrounded by a broken line 541corresponds to a portion in which there is formed the pixel portion, theportion surrounded by a broken line 542 corresponds to a portion inwhich there is formed the signal line driving circuit, and the portionsurrounded by a broken line 543 corresponds to a portion in which thereis formed the scanning line driving circuit. Reference numeral 544represents a portion (marker-forming portion) in which there is formed amarker, with this portion being provided and positioned at four cornersof the semiconductor film.

[0084] It should be noted here that four marker-forming portions 544 arerespectively provided at the four corners in FIG. 7A, although thepresent invention is not limited to this construction. The positions ofthe marker-forming portions and the number thereof are not limited tothe form described above so long as it is possible to align each portionto be scanned with the laser lights of the semiconductor film and eachmask for patterning the semiconductor film.

[0085] In FIG. 7B, reference numeral 550 denotes a semiconductor filmformed on a substrate and broken lines 551 indicate scribe lines alongwhich the substrate is to be divided in a subsequent step. In FIG. 7B,it is possible to manufacture four semiconductor devices by dividing thesubstrate along the scribe lines 551. Note that the number ofsemiconductor devices obtained through the division is not limited tothis.

[0086] Reference numeral 552 represents a portion (marker-formingportion) in which there is formed a marker, with this portion beingprovided and positioned at four corners of the semiconductor film. Itshould be noted here that four marker-forming portions 552 arerespectively provided at the four corners in FIG. 7B, although thepresent invention is not limited to this construction. The positions ofthe marker-forming portions and the number thereof are not limited tothe form described above so long as it is possible to align each portionto be scanned with the laser lights of the semiconductor film and eachmask for the patterning of the semiconductor film.

[0087] It is possible to cite the YAG laser, CO₂ laser, and the like asrepresentative examples of the laser used to form the markers. Needlessto say, however, it is possible to form the markers using another laser.

[0088] Next, there will be described a production system for asemiconductor device that uses the laser apparatus of the presentinvention.

[0089] An operation flow of the production system of the presentinvention is shown in FIG. 8 as a flowchart. First, there is performedthe designing of a semiconductor device using CAD. Then, informationconcerning the shape of each designed mask for patterning asemiconductor film is inputted into a CPU possessed by the laserapparatus.

[0090] On the other hand, after an amorphous semiconductor film isformed over a substrate, the substrate, on which the amorphoussemiconductor film has been formed, is set in the laser apparatus. Then,markers are formed on the surface of the semiconductor film using alaser.

[0091] On the basis of inputted information concerning the masks, theCPU determines each portion to be scanned with laser lights withreference to the positions of the markers. Then, with reference to theformed markers, the laser lights are irradiated onto the portion to bescanned with the laser lights, thereby partially crystallizing thesemiconductor film.

[0092] Then, after the irradiation of the laser lights, apolycrystalline semiconductor film obtained by the irradiation of thelaser lights is patterned and etched, thereby forming island-likesemiconductor films. Following this, there is performed a step formanufacturing a TFT from these island-like semiconductor films. Theconcrete step for manufacturing the TFT differs depending on the shapeof the TFT. Representatively, however, a gate insulating film is formedand an impurity region is formed in the island-like semiconductor films.Then, an interlayer insulating film is formed so as to cover the gateinsulating film and a gate electrode, and a contact hole is establishedin the interlayer insulating film. In this manner, there is obtained anexposed part of the impurity region. Then, wiring is formed on theinterlayer insulating film so as to contact the impurity region throughthe contact hole.

[0093] It should be noted here that for the sake of comparison andcontrast, FIG. 9 shows a production flow for a conventionalsemiconductor device as a flowchart. As shown in FIG. 9, the designingof masks for a semiconductor device is performed using CAD. On the otherhand, an amorphous semiconductor film is formed over a substrate and thesubstrate, on which the amorphous semiconductor film has been formed, isset in a laser apparatus. Then, laser lights are scanned and irradiatedonto the entire surface of the amorphous semiconductor film, therebycrystallizing the entire surface of the amorphous semiconductor film.Then, markers are formed in a polycrystalline semiconductor filmobtained through the crystallization and island-like semiconductor filmsare formed by patterning the polycrystalline semiconductor film withreference to the markers. Then, a TFT is manufactured using theisland-like semiconductor films.

[0094] As described above, in contrast to a conventional case such asthe case shown in FIG. 9, in the production system of the presentinvention, markers are formed using a laser light prior to thecrystallization of an amorphous semiconductor film. Then, laser lightsare scanned in accordance with information concerning masks forpatterning the semiconductor film.

[0095] With the construction described above, it becomes possible tosave a time taken to irradiate the laser lights onto each portion to beremoved through patterning after the crystallization of thesemiconductor film, which makes it possible to shorten a time taken toirradiate the laser lights and also to improve the speed at which asubstrate is processed.

[0096] It should be noted here that FIG. 10 shows a flowchart of theproduction system of the present invention in the case where there isincluded a step for crystallizing the semiconductor film using acatalyst. In the case where a catalytic element is used, it ispreferable that there is used the technique disclosed in JP 07-130652 Aor JP 08-78329 A.

[0097]FIG. 10 differs from FIG. 8 in that FIG. 10 includes a step(NiSPC) for crystallizing an amorphous semiconductor film using Ni afterthe formation of this film. In the case where there is used thetechnique disclosed in JP 07-130652 A, for instance, a nickel-containinglayer is formed by applying a nickel acetate solution containing 10 ppmnickel on a weight basis onto the amorphous semiconductor film. Then,after a dehydrogenation step is performed for one hour at 500° C.,crystallization is performed by performing heat treatment for four to 12hours at 500 to 650° C. (for eight hours at 550° C., for instance). Notethat as to a usable catalytic element, an element such as germanium(Ge), iron (Fe), palladium (Pd), tin (Sn), lead (Pd), cobalt (Co),platinum (Pt), copper (Cu), or gold (Au) may be used in addition tonickel (Ni).

[0098] Then, in FIG. 10, the crystallinity of the semiconductor filmcrystallized by NiSPC is further enhanced using the irradiation of laserlights. A polycrystalline semiconductor film obtained by the laser lightirradiation contains the catalytic element and there is performed a step(gettering) for removing the catalytic element from the crystallinesemiconductor film after the laser light irradiation in FIG. 10. It ispossible to use the technique disclosed in JP 10-135468 A or JP10-135469 A to perform the gettering.

[0099] In more detail, phosphorus is added to a part of thepolycrystalline semiconductor film obtained after the laser irradiationand heat treatment is performed in a nitrogen atmosphere for five to 24hours at 550 to 800° C. (for 12 hours at 600° C., for instance). As aresult of this processing, the region of the polycrystallinesemiconductor film, in which there has been added the phosphorus,functions as a gettering site and it becomes possible to segregate thephosphorus existing in the polycrystalline semiconductor film in theregion in which the phosphorus has been added. Following this, byremoving the region of the polycrystalline semiconductor film, in whichthe phosphorous has been added, through patterning, it is possible toobtain island-like semiconductor films in which the density of thecatalytic element is reduced to 1×10¹⁷ atms/cm³ or below, preferably,around 1×10¹⁶ atms/cm³.

[0100] As described above, with the present invention, laser lights arenot scanned and irradiated on the entire surface of the semiconductorfilm but are scanned so that it is possible to crystallize at least eachindispensable portion. With the construction described above, it becomespossible to save a time taken to irradiate the laser lights onto eachportion to be removed through patterning after the crystallization ofthe semiconductor film and to significantly shorten a time taken toprocess one substrate.

[0101] Also, it is possible to change the widths of the paths of laserlights, so that it becomes possible to prevent a situation where theedges of the paths of the laser lights overlap a semiconductor obtainedthrough patterning. It is also possible to reduce damage inflicted on asubstrate by the irradiation of the laser lights onto each unnecessaryportion.

Embodiments

[0102] Hereinafter, there will be described embodiments of the presentinvention.

[0103] [Embodiment 1]

[0104] In this embodiment, there will be described an optical systemused for the laser apparatus of the present invention.

[0105]FIGS. 11A and 11B show a concrete construction of the opticalsystem used for the laser apparatus of the present invention. FIG. 11Ais a side view of the optical system of the laser apparatus of thepresent invention and FIG. 11B is a side view taken in the direction ofarrow B in FIG. 11A. Note that the side view taken in the direction ofarrow A in FIG. 11B corresponds to FIG. 11A.

[0106]FIGS. 11A and 11B respectively show an optical system in the casewhere four beam spots are combined into one beam spot. Note that in thepresent invention, the number of beam spots to be combined is notlimited to this and there occurs no problem so long as the number ofbeam spots to be combined is in a range of from two to eight.

[0107] Reference numerals 401, 402, 403, 404, and 405 each denote acylindrical lens and the optical system of this embodiment uses sixcylindrical lenses, although not shown in FIGS. 11A and 11B. FIG. 12 isa perspective view of the optical system shown in FIGS. 11A and 11B.Laser lights from different laser oscillation apparatuses are incidenton the cylindrical lenses 403, 404, 405, and 406, respectively.

[0108] Then, laser lights, whose beam spot shapes have been processed bythe cylindrical lenses 403 and 405, are incident on the cylindrical lens401. The beam spot shapes of the incident laser lights are processed bythe cylindrical lens and are irradiated onto an object to be processed400. Also, laser lights, whose beam spot shapes have been processed bythe cylindrical lenses 404 and 406, are incident on the cylindrical lens402. The beam spot shapes of the incident laser lights are processed bythe cylindrical lens and are irradiated onto the object to be processed400.

[0109] On the object to be processed 400, the beam spots of the laserlights are made to overlap each other and are combined into one beamspot.

[0110] It should be noted here that in this embodiment, the focaldistance of the cylindrical lenses 401 and 402 that are closest to theobject to be processed 400 is set at 20 mm and the focal distance of thecylindrical lenses 403 to 406 is set at 150 mm. In addition, in thisembodiment, each lens is set so that the incident angle θ₁ of laserlights from the cylindrical lenses 401 and 402 to the object to beprocessed 400 becomes 25° and the incident angle θ₂ of laser lights fromthe cylindrical lenses 403 to 406 to the cylindrical lenses 401 and 402becomes 10°.

[0111] It should be noted here that it is possible for a designer to setthe focal distance and incident angle of each lens as appropriate.Further, the number of cylindrical lenses is not limited to this and theoptical system used is not limited to cylindrical lenses. It issufficient that in the present invention, there is used an opticalsystem that is capable of processing the beam spot of a laser lightoscillated from each laser oscillation apparatus so that there isobtained a shape and energy density suited for the crystallization of asemiconductor film and of combining the beam spots of all laser lightsinto one beam spot by having the beam spots overlap each other.

[0112] It should be noted here that in this embodiment, there has beendescribed an example where four beam spots are combined. In this case,there are provided four cylindrical lenses, which respectivelycorrespond to four laser oscillation apparatuses, and two cylindricallenses that correspond to the four cylindrical lenses. In the case wherebeam spots, whose number is n (n=2, 4, 6, or 8), are combined, there areprovided n cylindrical lenses, which respectively correspond to n laseroscillation apparatuses, and n/2 cylindrical lenses that correspond tothe n cylindrical lenses. In the case where beam spots, whose number isn (n=3, 5, or 7), are combined, there are provided n cylindrical lenses,which respectively correspond to n laser oscillation apparatuses, and(n+1)/2 cylindrical lenses that correspond to the n cylindrical lenses.

[0113] It should be noted here that in order to prevent a situationwhere a returning light returns by following the optical path that thelight originally followed, it is preferable that the incident angle withrespect to a substrate is maintained at a degree that is larger than 0°and is smaller than 90°.

[0114] Also, in order to realize the uniform irradiation of laserlights, in the case where the shape of each beam that is a planeperpendicular to an irradiation surface and is not yet synthesized isregarded as a rectangle, if either of a plane containing a short side ofthe rectangle or a plane containing a long side of the rectangle isdefined as an incident surface, when the length of the short side orlong side contained in the incident surface is referred to as “W” andthe thickness of a substrate that is placed on the irradiation surfaceand has a transmission property with respect to the laser lights isreferred to as “d”, it is preferable that the incident angle θ of thelaser lights satisfies a condition of θ arctan (W/2d). It is requiredthat this condition is satisfied by each laser light before thesynthesizing. Note that when the paths of the laser lights do not existon the incident surface, the incident angle, at which the paths areprojected on the incident surface, is regarded as θ. If the laser lightsare incident at this incident angle θ, there occurs no interferencebetween a reflection light on the surface of the substrate and areflection light from the underside of the substrate, which makes itpossible to perform uniform irradiation of the laser lights. The abovedescription has been made by assuming that the refractive index of thesubstrate is one. In actual cases, many substrates have a refractiveindex of around 1.5 and a calculated value that is greater than theangle calculated in the above description is obtained if considerationis given to this numerical value. However, the energies on both sides ofthe beam spots in the longitudinal direction are attenuated, so that theeffect of the interference in these portions is small and there issufficiently obtained the effect of attenuating the interference at thecalculated value described above.

[0115] [Embodiment 2]

[0116] In this embodiment, there will be described an example ofchanging the size of the beam spot of the laser light while irradiatingthe laser lights.

[0117] The laser apparatus of the present invention grasps each portionthat should be scanned with the laser lights based on inputtedinformation concerning masks using the CPU. Further, in this embodiment,the length of the beam spot is changed in accordance with the shapes ofthe masks.

[0118]FIG. 13 shows an example of the relation between the shapes of themasks for patterning a semiconductor film and the length of the beamspot. Reference numeral 560 shows the shapes of the masks for patterningthe semiconductor film, and after the crystallization by laserirradiation, the semiconductor film is patterned in accordance with themasks.

[0119] Reference numerals 561 and 562 denote portions irradiated withthe laser lights. Note that reference numeral 561 represents eachportion scanned with a beam spot obtained by superimposing and combiningbeam spots of laser lights outputted from four laser oscillationapparatuses. On the other hand, reference numeral 562 indicates eachportion scanned with a beam spot obtained by superimposing and combiningbeam spots of laser lights outputted from two laser oscillationapparatuses.

[0120] The beam spot obtained by synthesizing laser lights outputtedfrom two laser oscillation apparatuses is obtained by terminating theoscillation by two laser oscillation apparatuses out of four laseroscillation apparatuses. In this case, however, it is important that twobeam spots outputted from remaining two laser oscillation apparatusesare made to overlap each other.

[0121] It should be noted here that in the case where the lengths ofbeam spots are changed halfway through the scanning of laser lights likein this embodiment, the changing of the beam spot lengths from a longside to a short side is more preferable than the changing thereof fromthe short side to the long side because there are stabilized the outputsfrom the laser oscillation apparatuses. Consequently, it is preferablethat the CPU gives consideration to the scanning order of the laserlights so that the beam spot lengths are changed from the long side tothe short side based on information concerning the shapes of masks.Further, it is possible to design the masks with consideration given tothe scanning order of the laser lights at a stage of designing the mask.

[0122] With the construction described above, it becomes possible tochange the widths of paths of laser lights, so that it becomes possibleto prevent a situation where the edges of the paths of the laser lightsare superimposed on a semiconductor obtained through patterning. It isalso possible to further reduce damage inflicted on a substrate by theirradiation of the laser lights onto each unnecessary portion.

[0123] It is possible to implement this embodiment in combination withthe first embodiment.

[0124] [Embodiment 3]

[0125] In this embodiment, there will be described an example wherelaser lights are blocked by a shutter possessed by an optical systemhalfway through the irradiation of the laser lights, thereby irradiatingthe laser lights only onto each predetermined portion.

[0126] The laser apparatus of the present invention grasps each portionthat should be scanned with the laser lights based on inputtedinformation concerning masks using the CPU. Further, in this embodiment,the laser lights are blocked using the shutter so that the laser lightsare irradiated only onto each portion that should be scanned. It isdesirable that during this operation, the shutter is capable of blockingthe laser lights and also is formed using a material with which there isprevented a situation where the shutter is deformed or damaged by thelaser lights.

[0127]FIG. 14 shows an example of the relation between the shapes of themasks for patterning a semiconductor film and portions to be irradiatedwith laser lights. Reference numeral 570 shows the shapes of the masksfor patterning the semiconductor film and after the crystallization bylaser irradiation, the semiconductor film is patterned in accordancewith the masks.

[0128] Reference numeral 571 shows each portion irradiated with thelaser lights. The broken lines specify each portion in which the laserlights were blocked by the shutter. In this embodiment, it is possibleto prevent the irradiation of the laser lights onto each portion forwhich crystallization is not required or it is possible to reduce theenergy densities of the laser lights even if the laser lights areirradiated onto such a portion. As a result, it becomes possible tofurther reduce damage inflicted on a substrate by the irradiation of thelaser lights onto unnecessary portions.

[0129] It is possible to implement this embodiment in combination withthe first embodiment or the second embodiment.

[0130] [Embodiment 4]

[0131] In this embodiment, there will be described an example wherechanging the scanning direction of the laser lights is changed.

[0132] By setting the irradiation direction of the laser lights so as tobe parallel to a direction in which carriers in channel formationregions move, there is obtained a situation where the growing directionof crystal grains in the semiconductor film overlaps the movingdirection of the carriers and it becomes possible to enhance themobility. Because of constraints concerning the designing of a circuit,however, there is a case where it is difficult to lay out all activelayers so that the channel formation regions are parallel to the carriermoving direction. In this case, it is preferable that the scanningdirection of the laser lights is changed in accordance with informationconcerning masks.

[0133]FIG. 15 shows an example of the relation between the shapes of themasks for patterning the semiconductor film and portions to beirradiated with the laser lights. Reference numerals 580 and 583 showthe shapes of the masks for patterning the semiconductor film and, afterthe crystallization by laser irradiation, the semiconductor film ispatterned in accordance with the masks. The masks given referencenumerals 580 and 583 are designed so that the directions, in whichcarriers move in channel formation regions, become perpendicular to eachother.

[0134] The laser apparatus of the present invention grasps each portionto be scanned with the laser lights using the CPU based on inputtedinformation concerning the masks. On the other hand, the carrier movingdirection in a channel formation region of each island-likesemiconductor film obtained through patterning is inputted into the CPUas information. Specifically, there is predetermined a laser lightscanning direction with respect to the shape of each active layer. Then,the CPU refers to the predetermined laser light scanning direction withrespect to the shape of the active layer and compares it with the shapeof each active layer obtained from the shapes of the masks, anddetermines the scanning direction of each portion to be scanned of thesemiconductor film.

[0135] Reference numeral 581 shows a portion on which the laser lightshave been irradiated when the laser lights were scanned in a horizontaldirection, with the scanning direction being parallel to the carriermoving direction of a portion that will become the channel formationregion of the island-like semiconductor film 580 obtained after thepatterning. Reference numeral 582 indicates a portion on which the laserlights were irradiated when the laser lights were scanned in a verticaldirection, with its scanning direction being parallel to the carriermoving direction of a portion that will become the channel formationregion of the island-like semiconductor film 583 obtained after thepatterning.

[0136] It should be noted here that as indicated by reference numerals584 to 587 in FIG. 15, the surface of the semiconductor film in eachportion, in which laser lights having different scanning directions aresuperimposed and irradiated, is placed in a rough state, so that thereis a possibility that there is exerted an adverse effect on thecharacteristics of a gate insulating film to be formed afterward and itis not preferable that such a semiconductor film is used as the activelayer of a TFT. Consequently, it is preferable that the scanningdirection and scanning portion of the laser lights are determined at astage of designing the masks and the layout of the masks is determinedso that the island-like semiconductor films are not disposed in suchportions in which the laser lights overlap each other.

[0137] Also, there occurs no problem even if the situation where theedge portions of the paths of the laser lights overlap the island-likesemiconductor films is prevented by changing the lengths of the beamspots of the laser lights in the center axis direction like in thesecond embodiment. Also, there occurs no problem even if the situationwhere the edge portions of the paths of the laser lights overlap theisland-like semiconductor films is prevented or the situation where thelaser lights overlap each other is prevented using a shutter like in thethird embodiment.

[0138] It is possible to implement this embodiment in combination withthe first to third embodiments.

[0139] [Embodiment 5]

[0140] In this embodiment, there will be described an example of amarker provided on a marker forming portion 423.

[0141]FIG. 16A shows the top view of markers of this embodiment.Reference numerals 421 and 422 denote markers (hereinafter referred toas the “reference markers”) that will function as reference pointsformed in a semiconductor film, with each of the reference markershaving a rectangular shape. All of the reference markers 421 aredisposed so that long sides of the rectangles extend in the horizontaldirection, with respective reference markers 421 being disposed in thevertical direction at regular intervals. All of the reference markers422 are disposed so that long sides of the rectangles extend in thevertical direction, with respective reference markers 422 being disposedin the horizontal direction at regular intervals.

[0142] The reference markers 421 become reference points with referenceto which there are determined the positions of the masks in the verticaldirection, while the reference markers 422 become reference points withreference to which there are determined the positions of the masks inthe horizontal direction. Reference numerals 424 and 425 denote markersfor the masks for patterning the semiconductor film, with each of themarkers having a rectangular shape. The positions of the masks for thesemiconductor patterning are determined so that the long sides of therectangular marker 424 are disposed in the horizontal direction and thelong sides of the rectangular marker 425 are disposed in the verticaldirection. In addition, the positions of the masks for the semiconductorpatterning are determined so that the masks are precisely positioned atthe center between two adjacent reference markers 421 that determine themarkers 424 and are also precisely positioned at the center between twoadjacent reference markers 422 that determine the markers 425.

[0143]FIG. 16B is a perspective view of the reference markers formed inthe semiconductor film. Parts of the semiconductor film 430 formed onthe substrate 431 are cut away by a laser in a rectangular shape and thecut-away portions function as the reference markers 421 and 422.

[0144] It should be noted here that the markers described in thisembodiment are just an example and the markers of the present inventionare not limited to these markers. There occurs no problem so long as itis possible to form the markers of the present invention prior to thecrystallization of the semiconductor film with the laser lights and alsoto use the markers even after the crystallization by the irradiation ofthe laser lights.

[0145] It is possible to implement this embodiment in combination withthe first to fourth embodiments.

[0146] [Embodiment 6]

[0147] In this embodiment, there will be described an optical systemused for eight laser oscillation apparatuses of the present invention.

[0148]FIGS. 17 and 18 show a concrete construction of the optical systemused for the laser apparatus of the present invention. FIG. 17 is a sideview of the optical system of the laser apparatus of the presentinvention and FIG. 18 is a side view taken in the direction of arrow Bin FIG. 17. Note that the side view taken in the direction of arrow A inFIG. 18 corresponds to FIG. 17.

[0149] This embodiment respectively show an optical system in the casewhere eight beam spots are combined into one beam spot. Note that in thepresent invention, the number of beam spots to be combined is notlimited to this and there occurs no problem so long as the number ofbeam spots to be combined is in a range of from two to eight.

[0150] Reference numerals 441 to 450 each denote a cylindrical lens andthe optical system of this embodiment uses twelve cylindrical lenses,although not shown in FIGS. 17 and 18. FIG. 19 is a perspective view ofthe optical system shown in FIGS. 17 and 18. Laser lights from differentlaser oscillation apparatuses are incident on the cylindrical lenses 441to 444, respectively.

[0151] Then, laser lights, whose beam spot shapes have been processed bythe cylindrical lenses 450 and 445, are incident on the cylindrical lens441. The beam spot shapes of the incident laser lights are processed bythe cylindrical lens 441 and are irradiated onto an object to beprocessed 440. Also, laser lights, whose beam spot shapes have beenprocessed by the cylindrical lenses 451 and 446, are incident on thecylindrical lens 442. The beam spot shapes of the incident laser lightsare processed by the cylindrical lens 442 and are irradiated onto anobject to be processed 440. Also, laser lights, whose beam spot shapeshave been processed by the cylindrical lenses 449 and 447, are incidenton the cylindrical lens 443. The beam spot shapes of the incident laserlights are processed by the cylindrical lens 443 and are irradiated ontothe object to be processed 440. Also, laser lights, whose beam spotshapes have been processed by the cylindrical lenses 452 and 448, areincident on the cylindrical lens 444. The beam spot shapes of theincident laser lights are processed by the cylindrical lens 444 and areirradiated onto the object to be processed 440.

[0152] On the object to be processed 440, the beam spots of the laserlights are made to overlap each other and are combined into one beamspot.

[0153] It should be noted here that in this embodiment, the focaldistance of the cylindrical lenses 441 and 442 that are closest to theobject to be processed 440 is set at 20 mm and the focal distance of thecylindrical lenses 445 to 452 is set at 150 mm. In addition, in thisembodiment, each lens is set so that the incident angle θ₁ of laserlights from the cylindrical lenses 441 and 452 to the object to beprocessed 440 becomes 25° and the incident angle θ₂ of laser lights fromthe cylindrical lenses 445 to 452 to the cylindrical lenses 441 and 442becomes 10°.

[0154] It should be noted here that it is possible for a designer to setthe focal distance and incident angle of each lens as appropriate.Further, the number of cylindrical lenses is not limited to this and theoptical system used is not limited to cylindrical lenses. It issufficient that in the present invention, there is used an opticalsystem that is capable of processing the beam spot of a laser lightoscillated from each laser oscillation apparatus so that there isobtained a shape and energy density suited for the crystallization of asemiconductor film and of combining the beam spots of all laser lightsinto one beam spot by having the beam spots overlap each other.

[0155] It should be noted here that in this embodiment, there has beendescribed an example where eight beam spots are combined. In this case,there are provided eight cylindrical lenses, which respectivelycorrespond to eight laser oscillation apparatuses, and four cylindricallenses that correspond to the eight cylindrical lenses.

[0156] This embodiment may be implemented by combining with Embodiments1 to 5.

[0157] [Embodiment 7]

[0158] In this embodiment, a method of manufacturing an active matrixsubstrate will be described with reference to FIGS. 25 to 28. Asubstrate on which a CMOS circuit, a driver circuit, and a pixel portionhaving a pixel TFT and a retention capacity are formed together isreferred to as an active matrix substrate for convenience.

[0159] First of all, a substrate 600 formed of glass such as bariumborosilicate glass and aluminum borosilicate glass is used in thisembodiment. The substrate 600 may be a quartz substrate, a siliconsubstrate, a metal substrate or stainless substrate, which has aninsulating film on the surface. The substrate 600 may be a plasticsubstrate having heat resistance, which withstands a processingtemperature in this embodiment.

[0160] Next, an amorphous semiconductor film 692 is formed on thesubstrate 601 by publicly known method (such as the sputtering method,LPCVD method and plasma CVD method) (FIG. 25A). In this embodiment, anamorphous semiconductor film is formed. However, micro-crystallinesemiconductor film and crystalline semiconductor film may be formed. Inaddition, a compound semiconductor film having an amorphous structuresuch as an amorphous silicon germanium film may be used.

[0161] The amorphous semiconductor film 692 is crystallized by using thelaser crystallization. The laser crystallization is conducted by usingthe laser apparatus of the present invention. In the present invention,the amorphous semiconductor film is crystallized in part according to amask information inputted into CPU of the laser apparatus. Of course,the crystallization may be conducted by using not only the lasercrystallization, but also being combined with another knowncrystallization method (thermal crystallization method using RTA and anannealing furnace or using metal elements promoting crystallization).

[0162] When a crystallization of an amorphous semiconductor film isconducted, it is preferable that the second harmonic through the fourthharmonic of basic waves is applied by using the solid state laser whichis capable of continuous oscillation in order to obtain a crystal inlarge grain size. Typically, it is preferable that the second harmonic(with a wavelength of 532 nm) or the third harmonic (with a wavelengthof 355 nm) of an Nd: YVO₄ laser (basic wave of 1064 nm) is applied.Specifically, laser beams emitted from the continuous oscillation typeYVO₄ laser with 10 W output is converted into a harmonic by using thenon-linear optical elements. Also, a method of emitting a harmonic byapplying crystal of YVO₄ and the non-linear optical elements into aresonator. Then, more preferably, the laser beams are formed so as tohave a rectangular shape or an elliptical shape by an optical system,thereby irradiating a substance to be treated. At this time, the energydensity of approximately 0.01 to 100 MW/cm² (preferably 0.1 to 10MW/cm²) is required. The semiconductor film is moved at approximately 10to 2000 cm/s rate relatively corresponding to the laser beams so as toirradiate the semiconductor film.

[0163] Note that, a gas laser or solid-state laser of continuousoscillation type or pulse oscillation type can be used. The gas lasersuch as an excimer laser, Ar laser, Kr laser and the solid-state lasersuch as YAG laser, YVO₄ laser, YLF laser, YAlO₃ laser, glass laser, rubylaser, alexandrite laser, Ti: sapphire laser, Y₂O₃ laser can be used asthe laser beam. Also, crystals such as YAG laser, YVO₄ laser, YLF laser,YAlO₃ laser wherein Cr, Nd, Er, Ho, Ce, Co, Ti, Yb or Tm is doped can beused as the solid-state laser. A basic wave of the lasers is differentdepending on the materials of doping, therefore a laser beam having abasic wave of approximately 1 μm is obtained. A harmonic correspondingto the basic wave can be obtained by the using non-linear opticalelements.

[0164] By the above-mentioned laser crystallization, the crystallizedregions 693, 694, and 695 are formed that is crystallized in part in theamorphous semiconductor film (FIG. 25B).

[0165] The island like semiconductor films 602 to 606 are formed fromthe crystallized regions 693, 694, and 695 by performing patterningprocessing the crystallized semiconductor film into desired shape thatis increased the crystallinity (FIG. 25C).

[0166] After the island like semiconductor films 602 to 606 are formed,a small amount of impurity element (boron or phosphorus) may be doped inorder to control a threshold value of the TFT.

[0167] Next, a gate insulating film 607 covering the island likesemiconductor films 602 to 606 is formed. The gate insulating film 607is formed by using an insulating film containing silicon with athickness of 40 to 150 nm by using plasma CVD method or sputteringmethod. In this embodiment, a silicon oxynitride film (compositionalratio: Si=32%, O=59%, N=7% and H=2%) with a thickness of 110 nm isformed by the plasma CVD method. Notably, the gate insulating film isnot limited to the silicon oxynitride film but an insulating filmcontaining other silicon may be used as a single layer or as a laminatedpad.

[0168] When a silicon oxide film is used, it is formed by mixingTetraethyl Orthosilicate (TEOS) and O₂ by plasma CVD method, which isdischarged under a condition with reaction pressure of 40 Pa, asubstrate temperature of 300 to 400° C. and high frequency (13.56 MHz)power density of 0.5 to 0.8 W/cm². Thermal annealing at 400 to 500° C.thereafter can give good characteristics to the silicon oxide filmproduced in this way as a gate insulating film.

[0169] Next, a first conductive film 608, which is 20 to 100 nm inthickness, and a second conductive film 609, which is 100 to 400 nm inthickness, is stacked on the gate insulating film 607. In thisembodiment, the first conductive film 608 formed by a TaN film with athickness of 30 nm and the second conductive film 609 formed by a W filmwith a thickness of 370 nm are stacked. The TaN film is formed by usingTa target to perform sputtering in an atmosphere containing nitrogen.The W film is formed by using W target to perform sputtering.Alternatively, it can be formed by thermal CVD method using tungstenhexafluoride (WF₆). In both cases, the use of the gate electrode needslow resistance. Therefore, the resistivity of the W film is desirably 20μΩcm or less. The low resistance of the W film can be achieved byincreasing the size of the crystal grains. However, when the W filmcontains a large amount of impurity element such as oxygen, thecrystallization is inhibited, which raises the resistance. Accordingly,in this embodiment, the W film is formed by the sputtering method usinghigh purity (purity of 99.9999%) W target and by taking the preventionof intrusion of impurity from a vapor phase during the film forming intospecial consideration. Thus, the resistivity of 9 to 20 μΩcm can beachieved.

[0170] While, in this embodiment, the first conductive film 608 is TaNand the second conductive film 609 is W, they are not limited inparticular. Both of them can be formed by an element selected from Ta,W, Ti, Mo, Al, Cu, Cr and Nd or an alloy material or a compound materialmainly containing the element. Alternatively, a semiconductor film, suchas a polycrystalline silicon film to which an impurity element such asphosphorus is doped, can be used. An AgPdCu alloy may be used. Acombination of the first conductive film formed by a tantalum (Ta) filmand the second conductive film formed by a W film, a combination of thefirst conductive film formed by a titan nitride (TiN) film and thesecond conductive film formed by a W film, a combination of the firstconductive film formed by a tantalum nitride (TaN) film and the secondconductive film formed by a W film, a combination of the firstconductive film formed by a tantalum nitride (TaN) film and the secondconductive film formed by an Al film, or a combination of the firstconductive film formed by a tantalum nitride (TaN) film and the secondconductive film formed by a Cu film is possible.

[0171] Further, the present invention is not limited to a two-layerstructure. For example, a three-layer structure may be adopted in whicha tungsten film, an alloy film of aluminum and silicon (Al—Si), and atitanium nitride film are sequentially laminated. Moreover, in case of athree-layer structure, tungsten nitride may be used in place oftungsten, an alloy film of aluminum and titanium (Al—Ti) may be used inplace of the alloy film of aluminum and silicon (Al—Si), and a titaniumfilm may be used in place of the titanium nitride film.

[0172] Note that, it is important that appropriate etching method orkinds of etchant is properly selected depending on the materials of aconductive film.

[0173] Next, masks 610 to 615 made of resist using photolithographymethod are formed, and first etching processing is performed thereon inorder to form electrodes and wires. The first etching processing isperformed under first and second etching conditions (FIG. 26B). Thefirst etching condition in this embodiment is to use Inductively CoupledPlasma (ICP) etching and to use CF₄ and Cl₂ and O₂ as an etching gas,whose amount of gases are 25/25/10 (sccm), respectively. 500 W of RF(13.56 MHz) power was supplied to a coil type electrode by 1 Pa pressurein order to generate plasma and then to perform etching. 150 W of RF(13.56 MHz) power was also supplied to a substrate side (test samplestage) and substantially negative self-bias voltage was applied. The Wfilm was etched under the first etching condition so as to obtain theend of the first conductive layer in a tapered form.

[0174] After that, the first etching condition is shifted to the secondetching condition without removing the masks 610 to 615 made of resist.Then, CF₄ and Cl₂ are used as etching gases. The ratio of the amounts offlowing gasses is 30/30 (sccm). 500 W of RF (13.56 MHz) power issupplied to a coil type electrode by 1 Pa pressure in order to generateplasma and then to perform etching for amount 30 seconds. 20 W of RF(13.56 MHz) power is also supplied to a substrate side (test samplestage) and substantially negative self-bias voltage is applied. Underthe second etching condition where CF₄ and Cl₂ are mixed, both W filmand TaN film were etched to the same degree. In order to etch withoutleaving a residue on the gate insulating film, the etching time may beincreased 10 to 20% more.

[0175] In the first etching processing, when the shape of the mask madeof resist is appropriate, the shape of the ends of the first and thesecond conductive layers are in the tapered form due to the effect ofthe bias voltage applied to the substrate side. The angle of the taperedportion is 15 to 45°. Thus, conductive layers 617 to 622 in a first formare formed which include the first conductive layers and the secondconductive layers (first conductive layers 617 a to 622 a and secondconductive layer 617 b to 622 b) through the first etching processing.In a gate insulating film 616, an area not covered by the conductivelayers 617 to 622 in the first form is etched by about 20 to 50 nm so asto form a thinner area.

[0176] Next, second etching processing is performed without removingmasks made of resist (FIG. 26C). Here, CF₄, Cl₂ and O₂ are used as anetching gas to etch the W film selectively. Then, second conductivelayers 628 b to 633 b are formed by the second etching processing. Onthe other hand, the first conductive layers 617 a to 622 a are hardlyetched, and conductive layers 628 to 633 in the second form are formed.

[0177] First doping processing is performed without removing masks madeof resist and low density of impurity element, which gives n-type to thesemiconductor layer, is added. The doping processing may be performed bythe ion-doping method or the ion-implanting method. The ion dopingmethod is performed under a condition in the dose of 1×10¹³ to 5×10¹⁴atoms/cm² and the accelerating voltage of 40 to 80 kV. In thisembodiment, the ion doping method is performed under a condition in thedose of 1.5×10¹³ atoms/cm² and the accelerating voltage of 60 kV. Then-type doping impurity element may be Group 15 elements, typicallyphosphorus (P) or arsenic (As). Here, phosphorus (P) is used. In thiscase, the conductive layers 628 to 633 function as masks for the n-typedoping impurity element. Therefore, impurity areas 623 to 627 are formedin the self-alignment manner. An n-type doping impurity element in thedensity range of 1×10¹⁸ to 1×10²⁰ atoms/cm³ are added to the impurityareas 623 to 627.

[0178] When masks made of resist are removed, new masks 634 a to 634 cmade of resist are formed. Then, second doping processing is performedby using higher accelerating voltage than that used in the first dopingprocessing. The ion doping method is performed under a condition in thedose of 1×10¹³ to 1×10¹⁵ atoms/cm² and the accelerating voltage of 60 to120 kV. In the doping processing, the second conductive layers 628 b to632 b are used as masks against the impurity element. Doping isperformed such that the impurity element can be added to thesemiconductor layer at the bottom of the tapered portion of the firstconductive layer. Then, third doping processing is performed by havinglower accelerating voltage than that in the second doping processing toobtain a condition shown in FIG. 27A. The ion doping method is performedunder a condition in the dose of 1×10¹⁵ to 1×10¹⁷ atoms/cm² and theaccelerating voltage of 50 to 100 kV. Through the second dopingprocessing and the third doping processing, an n-type doping impurityelement in the density range of 1×10¹⁸ to 5×10¹⁹ atoms/cm³ is added tothe low density impurity areas 636, 642 and 648, which overlap with thefirst conductive layer. An n-type doping impurity element in the densityrange of 1×10¹⁹ to 5×10²¹ atoms/cm³ is added to the high densityimpurity areas 635, 641, 644 and 647.

[0179] With proper accelerating voltage, the low density impurity areaand the high density impurity area can be formed by performing thesecond doping processing and the third doping processing once.

[0180] Next, after removing masks made of resist, new masks 650 a to 650c made of resist are formed to perform the fourth doping processing.Through the fourth doping processing, impurity areas 653, 654, 659 and660, to which an impurity element doping a conductive type opposite tothe one conductive type is added, in a semiconductor layer, which is anactive layer of a p-channel type TFT. Second conductive layers 628 a to632 a are used as mask against the impurity element, and the impurityelement giving p-type is added so as to form impurity areas in theself-alignment manner. In this embodiment, the impurity areas 653, 654,659 and 660 are formed by applying ion-doping method using diborane(B₂H₆) (FIG. 27B). During the fourth doping processing, thesemiconductor layer forming the n-channel TFT is covered by masks 650 ato 650 c made of resist. Thorough the first to the third dopingprocessing, phosphorus of different densities is added to each of theimpurity areas 653, 654, 659 and 660. Doping processing is performedsuch that the density of p-type doping impurity element can be 1×10¹⁹ to5×10²¹ atoms/cm³ in both areas. Thus, no problems are caused when theyfunction as the source region and the drain region of the p-channel TFT.

[0181] Impurity areas are formed in the island like semiconductorlayers, respectively, through the processes above.

[0182] Next, the masks 650 a to 650 c made of resist are removed and afirst interlayer insulating film 661 is formed thereon. The firstinterlayer insulating film 661 may be an insulating film with athickness of 100 to 200 nm containing silicon, which is formed by plasmaCVD method or sputtering method. In this embodiment, silicon oxynitridefilm with a thickness of 150 nm is formed by plasma CVD method. Thefirst interlayer insulating film 661 is not limited to the siliconoxynitride film but may be the other insulating film containing siliconin a single layer or in a laminated pad.

[0183] Next, as shown in FIG. 27C, activation processing is performed byusing laser irradiation method. When a laser annealing method is used,the laser used in the crystallization can be used. When the activationprocessing is performed, the moving speed is same as thecrystallization, and an energy density of about 0.01 to 100 MW/cm(preferably, 0.01 to 10 MW/cm²) is required. Also, a continuousoscillation laser may be used in the case the crystallization isperformed and a pulse oscillation laser may be used in the case theactivation is performed.

[0184] Also, the activation processing may be conducted before the firstinterlayer insulating film is formed.

[0185] After the heating processing (thermal processing at 300 to 550°C. for 1 to 12 hours) is performed, hydrogenation can be performed. Thisprocess terminates the dangling bond of the semiconductor layer withhydrogen contained in the first interlayer insulating film 661.Alternatively, the hydrogenation may be plasma hydrogenation (usinghydrogen excited by plasma) or heating processing in an atmospherecontaining 3 to 100% of hydrogen at 300 to 650° C. for 1 to 12 hours.

[0186] Next, a second interlayer insulating film 662 formed by aninorganic insulating material or an organic insulator material is formedon the first interlayer insulating film 661. In this embodiment, anacrylic resin film with a thickness of 1.6 μm is formed. However, anacrylic resin film whose viscosity is 10 to 1000 cp, preferably 40 to200 cp and which may have depressions and projections formed on thesurface may be used.

[0187] In this embodiment, in order to prevent mirror reflection, asecond interlayer insulating film having projections and depressions onthe surface is formed. Thus, the projections and depressions are formedon the surface of the pixel electrode. In order to obtain an effect oflight dispersion by forming the depressions and projections on thesurface of the pixel electrode, a projecting portion may be formed underthe pixel electrode. In this case, the projecting portion can be formedby using the same photomask for forming a TFT. Thus, the projectingportion can be formed without any increase in the number of steps. Theprojecting portion may be provided as necessary on the substrate in thepixel area except for wirings and the TFT portion. Accordingly,projections and depressions can be formed on the surface of the pixelelectrode along the projections and depressions formed on the surface ofan insulating film covering the projecting portion.

[0188] Alternatively, the second interlayer insulating film 662 may be afilm having a flattened surface. In this case, after the pixel electrodeis formed, projections and depressions are formed on the surface byperforming an added process such as publicly known sand-blast method andetching method. Preferably, by preventing mirror reflection and bydispersing reflected light, the whiteness is increased.

[0189] Subsequently, the third interlayer insulating film 672 is formedto contact with the second interlayer insulating film 662 after thesecond interlayer insulating film is formed.

[0190] Wirings 663 to 667 electrically connecting to impurity areas,respectively, are formed in a driver circuit 686. These wirings areformed by patterning a film laminating a Ti film with a thickness of 50nm and an alloy film (alloy film of Al and Ti) with a thickness of 500nm. It is not limited to the two-layer structure but may be a one-layerstructure or a laminate pad including three or more layers. Thematerials of the wirings are not limited to Al and Ti. For example, thewiring can be formed by forming Al or Cu on a TaN film and then bypatterning the laminate film in which a Ti film is formed (FIG. 28).

[0191] In a pixel portion 687, a pixel electrode 670, a gate wiring 669and a connecting electrode 668 are formed. Source wirings (a laminate oflayers 633 a and 633 b) are electrically connected with a pixel TFT 684by the connecting electrode 668. The gate wiring 669 is electricallyconnected with a gate electrode of the TFT pixel 684. A pixel electrode670 is electrically connected with a drain region of the pixel TFT 684.Furthermore, the pixel electrode 670 is electrically connected with asemiconductor layer 606 functioning as one electrode forming a storagecapacitor. Desirably, a material having excellent reflectivity such as afilm mainly containing Al or Ag or the laminate film is used for thepixel electrode 670.

[0192] In this way, the driver circuit 686 having a CMOS circuitincluding an n-channel TFT 681 and a p-channel TFT 682 and a n-channelTFT 683, and the pixel portion 687 having the pixel TFT 684 and theretention capacitor 685 can be formed on the same substrate. Thus, anactive matrix substrate is completed.

[0193] The n-channel TFT 681 of the driver circuit 686 has a channelforming region 637, a low density impurity area 636 overlapping with thefirst conductive layer 628 a, which constructs a part of the gateelectrode (GOLD area), and a high density impurity area 652 functioningas the source region or the drain region are implanted. The p-typechannel TFT 682 forming a CMOS circuit together with the n-channel TFT681, which are connected by an electrode 666, has a channel formingregion 640, a high density impurity area 653 functioning as the sourceregion or the drain region, and an impurity area 654 to which a p-typedoping impurity element are implanted. The n-channel TFT 683 has achannel forming region 643, a low density impurity area 642 overlappingwith the first conductive layer 630 a, which constructs a part of thegate electrode, (GOLD area), and a high density impurity area 656functioning as the source region or the drain region.

[0194] The pixel TFT 684 of the pixel portion has a channel formingregion 646, a low density impurity area 645 formed outside of the gateelectrode (LDD region) and a high density impurity area 658 functioningas the source region or the drain region. An n-type doping impurityelement and a p-type doping impurity element are added to asemiconductor layer functioning as one electrode of the storagecapacitor 685. The storage capacitor 685 is formed by an electrode (alaminate of layers 632 a and 632 b) and a semiconductor layer by usingthe insulating film 616 as a dielectric.

[0195] The pixel structure in this embodiment is arranged such thatlight can be blocked in a space between pixel electrodes and the ends ofthe pixel electrodes can overlap with the source wiring without usingthe black matrix.

[0196] This embodiment can be implemented by combining with Embodiments1 to 8.

[0197] [Embodiment 8]

[0198] This embodiment explains, below, a process to manufacture areflection type liquid crystal display device from the active matrixsubstrate made in Embodiment 7, using FIG. 29.

[0199] First, after obtaining an active matrix substrate in the state ofFIG. 28 according to Embodiment 7, an orientation film 867 is formed atleast on the pixel electrodes 670 on the active matrix substrate of FIG.28 and subjected to a rubbing process. Incidentally, in this embodiment,prior to forming an orientation film 867, an organic resin film such asan acryl resin film is patterned to form columnar spacers 872 in adesired position to support the substrates with spacing. Meanwhile,spherical spacers, in place of the columnar spacers, may be distributedover the entire surface of the substrate.

[0200] Then, a counter substrate 869 is prepared. Then, coloring layers870, 871 and a planarizing film 873 are formed on a counter substrate869. A shade portion is formed by overlapping a red coloring layer 870and a blue coloring layer 871 together. Meanwhile, the shade portion maybe formed by partly overlapping a red coloring layer and a greencoloring layer.

[0201] In this embodiment is used a substrate shown in Embodiment 7.There is a need to shade at least the gap between the gate wiring 669and the pixel electrode 670, the gap between the gate wiring 669 and theconnecting electrode 668, and the gap between the connecting electrode668 and the pixel electrode 670. In this embodiment were bonded togetherthe substrates by arranging the coloring layers so that the shadingportion having a lamination of coloring layers is overlapped with theto-be-shading portion.

[0202] In this manner, the gaps between the pixels are shaded by theshading portion having a lamination of coloring layers without forming ashading layer such as a black matrix, thereby enabling to reduce thenumber of processes.

[0203] Then, a counter electrode 876 of a transparent conductive film isformed on the planarizing film 873 at least in the pixel portion. Anorientation film 874 is formed over the entire surface of the countersubstrate and subjected to a rubbing process.

[0204] Then, the active matrix substrate formed with the pixel portionand driver circuit and the counter substrate are bonded together by aseal member 868. The seal member 868 is mixed with filler so that thefiller and the columnar spacers bond together the two substrates throughan even spacing. Thereafter, a liquid crystal material 875 is pouredbetween the substrates, and completely sealed by a sealant (not shown).The liquid crystal material 875 may be a known liquid crystal material.In this manner, completed is a reflection type liquid crystal displaydevice shown in FIG. 29. If necessary, the active matrix substrate orcounter substrate is divided into a desired shape. Furthermore, apolarizing plate (not shown) is bonded only on the counter substrate.Then, an FPC is bonded by a known technique.

[0205] The liquid crystal display device manufactured as above comprisesTFT manufactured by a semiconductor film, wherein a laser beam having aperiodic or uniform energy distribution is irradiated and a crystalgrain with a large grain size is formed. Thus, the liquid crystaldisplay device ensures a good operational characteristic and highreliability. The liquid crystal display device can be used as a displayportion for an electronic appliance in various kinds.

[0206] Incidentally, this embodiment can be implemented by combiningwith Embodiments 1 to 7.

[0207] [Embodiment 9]

[0208] This embodiment explains an example of manufacturing a lightemitting device by using a method of manufacturing TFT when an activematrix substrate is fabricated in the Embodiment 7. In thisspecification, the light-emitting device refers, generally, to thedisplay panel having light-emitting elements formed on a substratesealed between the substrate and a cover member, and the display modulehaving TFTs or the like mounted on the display panel. Incidentally, thelight emitting element has a layer including an organic compound thatelectroluminescence caused is obtained by applying an electric field(light emitting layer), an anode layer and a cathode layer. Meanwhile,the electroluminescence in compound includes the light emission uponreturning from the singlet-excited state to the ground state(fluorescent light) and the light emission upon returning from thetriplet-excited state to the ground state (phosphorous light), includingany or both of light emission.

[0209] Note that, all the layers that are provided between an anode anda cathode in a light emitting element are defined as an organic lightemitting layer in this specification. Specifically, the organic lightemitting layer includes a light emitting layer, a hole injection layer,an electron injection layer, a hole transporting layer, an electrontransporting layer, etc. A basic structure of a light emitting elementis a laminate of an anode layer, a light emitting layer, and a cathodelayer layered in this order. The basic structure can be modified into alaminate of an anode layer, a hole injection layer, a light emittinglayer, and a cathode layer layered in this order, or a laminate of ananode layer, a hole injection layer, a light emitting layer, an electrontransporting layer, and a cathode layered in this order.

[0210] The light emitting element comprising the hole injection layer,the electron injection layer, the hole transporting layer, and theelectron transporting layer may be solely formed by inorganic compounds,or materials mixed with organic compounds and inorganic compounds. Thelight emitting element may be formed by mixture of these layers.

[0211]FIG. 30A is a sectional view of a light-emitting device of thisembodiment manufactured up through the third interlayer insulating film750. In FIG. 30A, the switching TFT 733 and the current controlling TFT734 provided on the substrate 700 is formed by using the manufacturingmethod in Embodiment 7. Incidentally, although this embodiment is of adouble gate structure formed with two channel forming regions, it ispossible to use a single gate structure formed with one channel formingregion or a triple gate structure formed with three channel formingregions.

[0212] The n-channel TFT 731 and the p-channel TFT 732 in the drivercircuit provided on the substrate 700 is formed by using themanufacturing method in Embodiment 7. Incidentally, although thisembodiment is of a single gate structure, it is possible to use a doublegate structure or a triple gate structure.

[0213] In the case of the light-emitting device, the third interlayerinsulating film 750 is effective to prevent water contained in thesecond interlayer insulating film 751 from penetrating into the organiclight emitting layer. If the second interlayer insulating film 751 hasorganic resin material, providing the third interlayer insulating film750 is effective because the organic resin materials contain water alot.

[0214] Completed the manufacture process up through the step of formingthe third interlayer insulating film in Embodiment 7, the pixelelectrode 711 is formed on the third interlayer insulating film 750.

[0215] Meanwhile, reference numeral 711 is a pixel electrode (anode of alight-emitting element) formed by a transparent conductive film. As thetransparent conductive film can be used a compound of indium oxide andtin oxide, a compound of indium oxide and zinc oxide, zinc oxide, tinoxide or indium oxide. A transparent conductive film added with galliummay also be used. The pixel electrode 711 is formed on a planar thirdinterlayer insulating film 750 prior to forming the wirings. In thisembodiment, it is very important to planarize the step due to the TFT byusing a the second interlayer insulating film 751 made of resin. A lightemitting layer to be formed later, because being extremely thin,possibly causes poor light emission due to the presence of a step.Accordingly, it is desired to provide planarization prior to forming apixel electrode so that a light emitting layer can be formed as planaras possible.

[0216] After the pixel electrode 711 is formed, contact holes are formedin the gate insulating film 752, the first interlayer insulating film753, the second interlayer insulating film 751, the third interlayerinsulating film 750, respectively. The conductive film is formed tooverlap the pixel electrode 711 on the third interlayer insulating film750, and the resist 760 is formed. Wirings 701 to 707 are formedconnected electrically to each impurity region of TFT by etching theconductive film using the resist 760. Note that a lamination film of a50 nm thick Ti film and a 500 nm thick alloy film (Al and Ti alloy film)is patterned in order to form the wirings. There are no limitationsregarding the two layer structure, of course, and a single layerstructure or a laminate structure having three or more layers may alsobe used. Further, the wiring material is not limited to Al and Ti. Forexample, a lamination film, in which Al or Cu is formed on a TaN film,and then a Ti film is formed, may be patterned, forming the wirings(FIG. 30B).

[0217] The wiring 707 is a source wiring (corresponding to the currentsupply line) of the current controlling TFT 734. Reference numeral 706is an electrode that connects to the pixel electrode 711 by overlappingwith the pixel electrode 711 of the current controlling TFT 734.

[0218] After forming wirings 701 to 707, the passivation film 712 isformed without removing resist 760 as shown in FIG. 30B. The passivationfilm 712 is formed to overlap the wirings 701 to 707, the thirdinterlayer insulating film 750, and the resist 760. The passivation film712 is composed of a silicon nitride film, a silicon oxynitride film, analuminum nitride, or an insulating film containing aluminum oxynitride.The insulating films are used in a single layer or a combinedlamination. A part of the pixel electrode 711 is exposed by etching thepassivation film 712.

[0219] A light emitting layer 713 is formed on the pixel electrode 711.Incidentally, although FIG. 30B shows only one pixel, this embodimentseparately forms light emitting layers correspondingly to the respectivecolors of R (red), G (green) and B (blue). Meanwhile, in this embodimentis formed a low molecular weight organic light-emitting material by thedeposition method. Specifically, this is a lamination structure having acopper phthalocyanine (CuPc) film provided with a thickness of 20 nm asa hole injecting layer and a tris-8-qyuinolinolato aluminum complex(Alq₃) film provided thereon with a thickness of 70 nm as a lightemitting layer. The color of emission light can be controlled by addinga fluorescent pigment, such as quinacridone, perylene or DCM1, to Alq₃.

[0220] However, the foregoing example is an example of organiclight-emitting material to be used for a light emitting layer and notnecessarily limited to this. It is satisfactory to form a light emittinglayer (layer for light emission and carrier movement therefore) byfreely combining a light emitting layer, a charge transporting layer anda charge injection layer. For example, although in this embodiment wasshown the example in which a low molecular weight organic light-emittingmaterial is used for a light emitting layer, it is possible to use anintermediate molecular weight organic light-emitting material or highmolecular weight organic light-emitting material. In this specification,an intermediate molecular weight organic light-emitting material can bedefined that an aggregate of an organic compound which does not havesubliming property or dissolving property (preferably, an aggregatewhich has molecularity of 10 or less), or an organic compound which hasa molecular chain length of 5 μm of less (preferably 50 nm or less). Asan example of using high molecular electroluminescent emitting material,the laminated pad can be made polythiophene (PEDOT) films with athickness of 20 nm is provided by spin coating method as a holeinjection layer, and paraphenylene-vinylene (PPV) films with a thicknessof 100 nm is provided thereon as a light emitting layer. The lightemitting wave length can be selected from red through blue by usingπ-conjugated system high molecular of PPV. The inorganic material suchas a silicon carbide can be used as a charge transporting layer and acharge injection layer. These organic light-emitting material andinorganic light-emitting material are formed by using known materials.

[0221] Next, a cathode 714 of a conductive film is provided on the lightemitting layer 713. In this embodiment, as the conductive film is usedan alloy film of aluminum and lithium. A known MgAg film (alloy film ofmagnesium and silver) may be used. As the cathode material may be used aconductive film of an element belonging to the periodic-table group 1 or2, or a conductive film added with such an element.

[0222] A light-emitting element 715 is completed at a time having formedup to the cathode 714. Incidentally, the light-emitting element 715herein refers to a diode formed with a pixel electrode (anode) 711, alight emitting layer 713 and a cathode 714.

[0223] It is effective to provide a protective film 754 in such a mannerto completely cover the light-emitting element 715. The protective film754 is formed by an insulating film including a carbon film, a siliconnitride film or a silicon oxynitride film, and used is an insulatingfilm in a single layer or a combined lamination.

[0224] In such a case, it is preferred to use a film favorable incoverage as a protective film 754. It is effective to use a carbon film,particularly DLC (diamond-like carbon) film. The DLC film, capable ofbeing deposited in a temperature range of from room temperature to 100°C. or less, can be easily deposited over the light emitting layer 713low in heat resistance. Meanwhile, the DLC film, having a high blockingeffect to oxygen, can suppress the light emitting layer 713 fromoxidizing. Consequently, prevented is the problem of oxidation in thelight emitting layer 713 during the following seal process.

[0225] In this embodiment, the light emitting layer 713 is overlappedcompletely with a inorganic insulating film having high barrier propertysuch as a carbon film, a silicon nitride, a silicon oxynitride, aluminumnitride, or aluminum oxynitride, so that it can prevent effectively thedeterioration of the light emitting layer due to water and oxygen frompenetrating thereof into the light emitting layer.

[0226] Furthermore, it is preferable to use the silicon nitride filmformed by sputtering method using silicon as a target for the thirdinterlayer insulating film 750, the passivation film 712, the protectivefilm 754 that the penetration of impurities into the light emittinglayer is prevented effectively. The deposition condition may beappropriately selected, preferably, nitride (N₂) or a mixed gas ofnitride and argon are used for sputtering gas, and sputtering isperformed by applying a high frequency electric. The substratetemperature may be set as room temperature, and heating means areunnecessary to be used. If the organic insulating film and the organiccompound layer are formed already, it is preferable that the depositionis conducted without heating the substrate. However, to removecompletely absorbed water or occluded water, it is preferable to performdehydration by heating for several minutes to hours in vacuum at about50 to 100° C.

[0227] The silicon nitride film formed by sputtering method at thecondition: at room temperature using silicon as a target; applying 13.56MHz high frequency electric; and using nitride gas is characterized inthat not observed the absorption peak of N—H association and Si—Hassociation in the infrared absorption spectrum and the absorption peakif Si—O. The oxide density and the hydrogen density is not more than 1atomic %. Thus, it can prevent more effectively impurities such asoxygen and water more effectively from penetrating into the lightemitting layer.

[0228] Furthermore, a seal member 717 is provided to overlap the lightemitting layer 715 to bond a cover member 718. For the seal member 717used may be an ultraviolet curable resin. It is effective to providetherein a substance having a hygroscopic effect or an antioxidanteffect. Meanwhile, in this embodiment, for the cover member 718 used isa glass substrate, quartz substrate or plastic substrate (including aplastic film) having carbon films (preferably diamond-like carbon films)formed on the both surfaces thereof.

[0229] Thus, completed is a light-emitting device having a structure asshown in FIG. 30B. Incidentally, it is effective to continuously carryout, without release to the air, the process to form a protective filmafter forming a passivation film 712 by using a deposition apparatus ofa multi-chamber scheme (or in-line scheme). In addition, with furtherdevelopment it is possible to continuously carry out the process up tobonding a cover member 718, without release to the air.

[0230] In this manner, n-channel TFTs 731, p-channel TFT 732, aswitching TFT (n-channel TFT) 733 and a current control TFT (p-channelTFT) 734 are formed on the substrate 700.

[0231] Furthermore, as was explained using FIG. 30, by providing animpurity region overlapped with the gate electrode through an insulatingfilm, it is possible to form an n-channel TFT resistive to thedeterioration resulting from hot-carrier effect. Consequently, areliable light emitting device can be realized.

[0232] Meanwhile, this embodiment shows only the configuration of thepixel portion and driver circuit. However, according to themanufacturing process in this embodiment, besides there, it is possibleto form logic circuits such as a signal division circuit, a D/Aconverter, an operation amplifier, a γ-correction circuit on a sameinsulator. Furthermore, a memory or microprocessor can be formed.

[0233] The light emitting device manufactured, wherein a laser beamhaving a periodic or uniform energy distribution is irradiated and acrystal grain with a large grain size is formed. Thus, the lightemitting device ensures a good operational characteristic and highreliability. The light emitting device can be used as a display portionfor an electronic appliance in various kinds.

[0234] Incidentally, this embodiment can be implemented by combining anyone of Embodiments 1 to 7.

[0235] [Embodiment 10]

[0236] This embodiment will be described SEM of a semiconductor filmcrystallized by the laser irradiation.

[0237] In this embodiment, a glass film is formed as a base film withplasma CVD method, and a silicon oxynitride film (compositional ratio:Si=32%, O=59%, N=7%, H=2%) with a thickness of 400 nm. Subsequently, anamorphous silicon film with a thickness of 150 nm are laminated on thebase film as a semiconductor film with plasma CVD method. After hydrogencontained in the semiconductor film is released by performing heattreatment at 500° C. for three hours, the semiconductor film iscrystallized by a laser annealing method. The semiconductor film iscrystallized in that the laser annealing condition: a second harmonicwave of YVO₄ laser is used as a laser beam, an incident angles θ is setto 18° to form a rectangular shape beam, whereby irradiating thesemiconductor film to be the central beam spot at right angle to thescanning direction as moving the substrate at a speed of 50 cm/s.

[0238] A seco-etching is performed to the crystalline semiconductor filmthus obtained, and the result of observing the surface of thecrystalline semiconductor film with a SEM by one thousand times is shownin FIG. 20. Note that, the seco solution in the seco-etching is the onemade by using K₂Cr₂O₇ for HF: H₂O=2:1 as an additive. FIG. 20 wasobtained by relatively scanning the laser beam in the directionindicated by the arrow in figure, and FIG. 20 shows the appearance thatcrystal grains of large grain size is formed in a perpendiculardirection relative to the scanning direction.

[0239] Therefore, since the crystal grains of large grain size areformed in the semiconductor film wherein crystallization is conducted byusing the present invention, when TFT is fabricated by using thesemiconductor film, the number of crystal boundaries that may becontained in a channel forming region can be reduced. Further, since anindividual crystal grain has the crystallinity such that it can beregarded substantially single crystal, the high mobility (field effectmobility) equal to or more than that of a transistor using a singlecrystal semiconductor can be obtained.

[0240] In addition, since the formed crystal grains become complete inone direction, the number of crossing across the crystal grain boundaryby a carrier can be remarkably reduced. Therefore, it is possible toreduce variations of an on current value (a value of a drain currentflowing in an on state of a TFT), an off current value (a value of adrain current flowing in an off state of a TFT), a threshold voltage, anS value, and field effect mobility. And electric characteristic isextremely improved.

[0241] [Embodiment 11]

[0242] This embodiment will be described SEM of a semiconductor filmcrystallized by the laser irradiation by applying a method recorded inJapanese Patent Laid-open No. Hei 7-183540.

[0243] In accordance with Embodiment 10, after the amorphous siliconfilm is formed, by applying a method recorded in Japanese PatentLaid-open No. Hei 7-183540, an aqueous nickel acetate solution (weightconverting concentration 5 ppm, volume 10 ml) is applied to the surfaceof the semiconductor film by spin coating to perform heat treatment inthe nitrogen atmosphere at 500° C. for one hour and in the nitrogenatmosphere at 550° C. for twelve hours. Subsequently, an improvement ofcrystallinity of the semiconductor film is performed by laser annealingmethod. The improvement of crystallinity of the semiconductor film isperformed under the condition of the laser annealing method that asecond harmonic wave of YVO₄ laser is used as a laser beam, an incidentangles θ is set to 18° to form a rectangular shape beam, wherebyirradiating the semiconductor film to be the central beam spot at rightangle to the scanning direction as moving the substrate at a speed of 50cm/s.

[0244] A seco-etching is performed to the crystalline semiconductor filmthus obtained, and the surface of the crystalline semiconductor film isobserved with the SEM by one thousand times. An observation result isshown in FIG. 21. The observation result in FIG. 21 was obtained byrelatively scanning the laser beam in the direction indicated by thearrow in figure, and FIG. 21 shows the appearance that crystal grains oflarge grain size is formed in a parallel direction relative to thescanning direction. Further, it is characteristics that crystal grainsshown in FIG. 21 has fewer grain boundaries formed in the directionwhich intersects to relative scanning direction of laser beam than thatshown in FIG. 20.

[0245] Therefore, since the crystal grains of large grain size areformed in the semiconductor film wherein crystallization is conducted byusing the present invention, when TFT is fabricated by using thesemiconductor film, the number of crystal boundaries that may becontained in a channel forming region can be reduced. Further, since anindividual crystal grain has the crystallinity such that it can beregarded substantially single crystal, the high mobility (field effectmobility) equal to or more than that of a transistor using a singlecrystal semiconductor can be obtained.

[0246] In addition, since the formed crystal grains become complete inone direction, the number of crossing across the crystal grain boundaryby a carrier can be remarkably reduced. Therefore, it is possible toreduce variations of an on current value, an off current value, athreshold voltage, an S value, and field effect mobility. And electriccharacteristic is extremely improved.

[0247] [Embodiment 12]

[0248] This embodiment will be described an example of forming TFT usingcrystallized semiconductor film according to Embodiment 10.

[0249] In this embodiment, a glass film is used as a base film, and asilicon oxynitride film (compositional ratio: Si=32%, O=27%, N=24%,H=17%) with a thickness of 50 nm, and a silicon oxynitride film(compositional ratio: Si=32%, O=59%, N=7%, H=2%) with a thickness of 100nm are laminated on the base film with plasma CVD method. Subsequently,an amorphous silicon film with a thickness of 150 nm is formed on thebase film as a semiconductor film by plasma CVD method. Hydrogencontained in the semiconductor film is released by performing heattreatment at 500° C. for three hours. Then, a second harmonic wave ofYVO₄ laser is used as a laser beam, and performing crystallizationaccording to the condition described in Embodiment 10.

[0250] Subsequently, a first doping processing is conducted. The firstdoping processing is a channel doping that controls a threshold value.The first doping processing is conducted by using B₂H₆ as a materialgas, setting the gas flow rate to 30 sccm, the current density to 0.05μA, the acceleration voltage to 60 kV, and the dose to 1×10¹⁴ atoms/cm².Subsequently, patterning is performed to etch a semiconductor film in apredetermined shape, and then a silicon oxynitride film with a thicknessof 115 nm is formed as a gate insulating film covering the etchedsemiconductor film by the plasma CVD method. Subsequently, a TaN filmwith a thickness of 30 nm and a W film with a thickness of 370 nm asconductive films are laminated on the gate insulating film.

[0251] A mask made of resist (not shown) is formed by photolithographyto etch the W film, the TaN film and the gate insulating film.Subsequently, introducing impurity elements which impart n-type to thesemiconductor film by second doping processing. In this case, conductivelayers are become masks with respect to the impurity elements impartingn-type respectively and an impurity region that is sandwiching thechannel forming region formed in a self-aligning manner. In thisembodiment, the second doping processing is divided into two conditionsto be performed since the film thickness of the semiconductor film isvery thick with 150 nm. In this embodiment, at first, the second dopingprocessing of the first condition is performed by using phosphine (PH₃)as a material gas, and setting a dose to 2×10¹³ atoms/cm² and theacceleration voltage to 90 kV. And then, the second doping processing ofthe second condition is performed by setting the dose to 5×10¹⁴atoms/cm² and the acceleration voltage to 10 kV.

[0252] Next, the mask made of a resist is removed, a new mask made ofresist is formed to cover the semiconductor film of the n-channel TFT,and the third doping processing is performed. By the third dopingprocessing, an impurity element for imparting a conductivity typeopposite to the one conductivity type is added to an impurity region.The impurity region is formed in the semiconductor film which becomes anactive layer of the p-channel TFT. The conductive layers are used as amask to the impurity element and the impurity element for imparting ap-type is added so as to form impurity region in a self-aligning manner.In this embodiment, the third doping processing is also divided into twoconditions to be performed since the film thickness of the semiconductorfilm is very thick with 150 nm. In this embodiment, the third dopingprocessing of the first condition is performed by using diborane (B₂H₆)as a material gas and setting the dose to 2×10¹³ atoms/cm², and theacceleration voltage to 90 kV. And then, the third doping processing ofthe second condition is performed by setting the dose to 1×10¹⁵atoms/cm², and the acceleration voltage to 10 kV.

[0253] By the steps until now, the impurity regions that is sandwichingthe channel forming region are formed in the respective semiconductorlayers.

[0254] Next, the mask made of resist is removed and a silicon oxynitridefilm with a thickness of 50 nm (compositional ratio: Si=32.8%, O=63.7%,H=3.5%) is formed as a first interlayer insulating film by plasma CVDmethod. Next, a recovery of crystallinity of the semiconductor layersand an activation of the impurity element added to the respectivesemiconductor layers are conducted by the heat treatment. In thisembodiment, the heat treatment is performed in a nitrogen atmosphere at550° C. for four hours by a thermal annealing method using an annealingfurnace.

[0255] Next, a second interlayer insulating film made of organicinsulating film materials or inorganic insulating materials are formedon a first interlayer insulating film. In this embodiment, a siliconnitride film with a thickness of 50 nm is formed by CVD method and thena silicon oxide film with a thickness of 400 nm is formed. Next, ahydrogenation processing can be carried out after the heat treatment. Inthis embodiment, the heat treatment is performed in a nitrogenatmosphere at 410° C. for one hour by using the annealing furnace.

[0256] Subsequently, a wiring electrically connecting to the respectiveimpurity regions is formed. In this embodiment, a lamination film of aTi film with a thickness of 50 nm, an Al—Si film with a thickness of 500nm, and a Ti film with a thickness of 50 nm is patterned to form. Ofcourse, it is not limited to a two layer structure, but also may be asingle layer structure or lamination structure of three layers or more.Further, materials for wirings are not limited to Al and Ti. Forexample, wirings may be formed by forming Al or Cu on the TaN film andpatterning the lamination film on which a Ti film is formed.

[0257] As described above, an n-channel TFT and a p-channel TFT areformed. An electric characteristic of the n-channel TFT is shown in FIG.22A and an electric characteristic of the p-channel TFT is shown in FIG.22B by measuring the electric characteristics. As the measurementcondition of the electric characteristics, measurement point is assumedto be two points, the gate voltage (Vg) is set to in the range of −16 to16 V, and the drain voltage (Vd) is set to 1 V and 5 V, respectively.Moreover, in FIGS. 22A and 22B, drain current (ID) and gate current (ID)are shown in a solid line and the mobility (μFE) is shown in a dottedfine.

[0258]FIGS. 22A and 22B show that the electric characteristics of TFTmanufactured by using the crystalline semiconductor film formed inEmbodiment 10 is remarkably improved. When TFT is manufactured by usingthe semiconductor film, the number of crystal grain boundaries that maybe contained in a channel forming region can be reduced, since a crystalgrain of large grain size is formed in the semiconductor film, which iscrystallized by using the present invention. Furthermore, since thecrystal grains are formed in the same direction, it is possible toreduce the number of crossing across the grain boundary by carrierremarkably. Therefore, the mobility is 524 cm²/Vs at the n-channel TFTand the mobility is 205 cm²/Vs at the p-channel TFT. When asemiconductor device is manufactured by using such TFT, the mobilitycharacteristic and the reliability of the semiconductor device can beimproved.

[0259] [Embodiment 13]

[0260] This embodiment will be described an example of forming TFT usingcrystallized semiconductor film according to Embodiment 11.

[0261] It forms to an amorphous silicon film as a semiconductor film inaccordance with Embodiment 11. Further, by applying a method recorded inJapanese Patent Laid-open No. Hei 7-183540, an aqueous nickel acetatesolution (weight converting concentration 5 ppm, volume 10 ml) isapplied to the surface of the semiconductor film by spin coating therebyforming a metal containing layer. Then heat treatment is performed inthe nitrogen atmosphere at 500° C. for one hour and in the nitrogenatmosphere at 550° C. for twelve hours. Subsequently, an improvement ofcrystallinity of the semiconductor film is performed by laser annealingmethod. The improvement of crystallinity of the semiconductor film isperformed by the laser annealing method under the conditions that asecond harmonic wave of YVO₄ laser is used as a laser beam according tothe condition described in Embodiment 11.

[0262] In accordance with the Embodiment 12, a n-channel TFT and ap-channel TFT are formed hereafter. The electric characteristics of then-channel TFT and the p-channel TFT are measured, and then an electriccharacteristic of the n-channel TFT is shown in FIG. 23A, an electriccharacteristic of the p-channel TFT is shown in FIG. 23B, respectively,in the laser annealing step. As the measurement condition of theelectric characteristics, the measurement point is assumed to be twopoints, the gate voltage (Vg) is set to in the range of −16 to 16 V, andthe drain voltage (Vd) is set to 1.5 V. Moreover, in FIGS. 23A to 23B,drain current (ID) and gate current (ID) is shown in solid line and themobility (μFE) is shown in dotted line.

[0263]FIGS. 23A to 23B show that the electric characteristics of TFTusing the semiconductor film manufactured in Embodiment 11 is remarkablyimproved. When TFT is manufactured by using the semiconductor film, thenumber of crystal grain boundaries that may be contained in a channelforming region can be reduced, since a crystal grain of large grain sizeis formed in the semiconductor film which is crystallized by using thepresent invention. Furthermore, since the formed crystal grains becomecomplete in one direction and there are few grain boundaries formed inthe direction crossed to the relative scanning direction of laser light,it is possible to reduce the number of crossing across the grainboundary by carrier remarkably. Therefore, it is understood that themobility is 595 cm²/Vs at the n-channel TFT and the mobility is 199cm²/Vs at the p-channel TFT, and these mobility is very excellent. Whena semiconductor device is manufactured by using such TFT, the mobilitycharacteristic and the reliability of the semiconductor device can beimproved.

[0264] [Embodiment 14]

[0265] Given as embodiments of electric equipment employing asemiconductor device formed by the laser apparatus of the presentinvention is applied are: a video camera; a digital camera; a goggletype display (head mounted display); a navigation system; an audioreproducing device (car audio, an audio component, and the like); alaptop computer; a game machine; a portable information terminal (amobile computer, a cellular phone, a portable game machine, anelectronic book, etc.); and an image reproducing device equipped with arecording medium (specifically, a device equipped with a display devicewhich can reproduce a recording medium such as a digital versatile disk(DVD), and can display the image). Specific examples of the electricequipment are shown in FIGS. 24A to 24H.

[0266]FIG. 24A shows a display device, which comprises a casing 2001, asupporting base 2002, a display portion 2003, speaker portions 2004, avideo input terminal 2005, etc. The light emitting device formed by thepresent invention is applied can be used for the display portion 2003.The semiconductor device is self-luminous and does not need a backlight,so that it can make a thinner display portion than liquid displaydevices can. The term display device includes every display device fordisplaying information such as one for a personal computer, one forreceiving TV broadcasting, and one for advertisement.

[0267]FIG. 24B shows a digital still camera, which comprises a main body2101, a display portion 2102, an image receiving portion 2103, operationkeys 2104, an external connection port 2105, a shutter 2106, etc. Thelight emitting device formed by the present invention is applied can beused for the display portion 2102, and other circuits.

[0268]FIG. 24C shows a laptop computer, which comprises a main body2201, a casing 2202, a display portion 2203, a keyboard 2204, anexternal connection port 2205, a pointing mouse 2206, etc. The lightemitting device formed by the present invention is applied can be usedfor the display portion 2203, and other circuits.

[0269]FIG. 24D shows a mobile computer, which comprises a main body2301, a display portion 2302, a switch 2303, operation keys 2304, aninfrared ray port 2305, etc. The light emitting device formed by thepresent invention is applied can be used for the display portion 2302,and other circuits.

[0270]FIG. 24E shows a portable image reproducing device equipped with arecording medium (a DVD player, to be specific). The device comprises amain body 2401, a casing 2402, a display portion A 2403, a displayportion B 2404, a recording medium (DVD or the like) reading portion2405, operation keys 2406, speaker portions 2407, etc. The displayportion A 2403 mainly displays image information whereas the displayportion B 2404 mainly displays text information. The light emittingdevice formed by the present invention is applied can be used for thedisplay portions A 2403 and B 2404, and other circuits. The term imagereproducing device equipped with a recording medium includes domesticgame machines.

[0271]FIG. 24F shows a goggle type display (head mounted display), whichcomprises a main body 2501, display portions 2502, and arm portions2503. The light emitting device formed by the present invention isapplied can be used for the display portions 2502, and other circuits.

[0272]FIG. 24G shows a video camera, which comprises a main body 2601, adisplay portion 2602, a casing 2603, an external connection port 2604, aremote control receiving portion 2605, an image receiving portion 2606,a battery 2607, an audio input portion 2608, operation keys 2609,eyepiece portion 2610 etc. The light emitting device formed by thepresent invention is applied can be used for the display portion 2602,and other circuits.

[0273]FIG. 24H shows a cellular phone, which comprises a main body 2701,a casing 2702, a display portion 2703, an audio input portion 2704, anaudio output portion 2705, operation keys 2706, an external connectionport 2707, an antenna 2708, etc. The light emitting device formed by thepresent invention is applied can be used for the display portion 2703,and other circuits. If the display portion 2703 displays whitecharacters on a black background, power consumption of the cellularphone can be reduced.

[0274] The light emitting device can be used also in a front or rearprojector besides above-mentioned electronic apparatuses.

[0275] As described above, the application range of the light emittingdevice to which the present invention is applied is very wide andelectric equipment of every field can employ the device. The electricequipments in this embodiment may use any configuration of semiconductordevices shown in Embodiments 1 to 13.

[0276] [Embodiment 15]

[0277] In general, a stage, on which an object to be processed byirradiating laser lights is mounted, is moved along a guide railprovided in the X direction and the Y direction. Also, between the guiderail and a portion (slider) to which the stage is fixed, there issandwiched an object having a curved surface that is called a ball(bearing) and there is provided a mechanism for realizing the smoothmoving of the stage by reducing a load due to friction.

[0278] It is required to replace this ball through periodicalmaintenance work because this ball is worn and torn as a result of therepeated moving of the stage. It is also required to further reduce thefriction caused during the moving of the stage in order to move thestage more smoothly.

[0279]FIG. 34A shows means (position control means) of this embodimentfor moving the stage. Reference numeral 7000 denotes a guide rail forwhich projections and depressions are formed along one direction inorder to move the stage in a fixed direction. Also, reference numeral7001 is a portion called a slider to which the stage is fixed and iscapable of being moved along the guide rail 7000. Also, a rod 7002 is anaxis passing through a hole established in the slider 7001 and isprovided in a direction along the guide rail. The rod 7002 is fixed tothe guide rail 7000 by end plates 7004.

[0280] A power supply voltage and air are sent to the slider 7001through a cable 7003. FIG. 34B is an enlarged view of the slider 7001.This slider 7001 generates, from the power supply voltage, a magneticfield with which the slider 7001 and the guide rail 7000 are attractedto each other. Also, the slider 7001 generates, from the power supplyvoltage, a magnetic field in a direction in which the rod 7002 isseparated from the hole established in the slider 7001 so as to preventthe contact between them. Also, on the other hand, the sent air isdischarged to a space between the slider 7001 and the guide rail 7000from air holes 7005. The distance between the slider 7001 and the guiderail 7000 is kept constant because a force in a direction, in which theslider 7001 and the guide 7000 are attracted to each other, is exertedas a result of this magnetic field and a force in a direction, in whichthe slider 7001 and the guide 7000 are separated from each other, isexerted as a result of the air discharging.

[0281] It should be noted here that the present invention is not limitedto the case where the magnetic field is generated by the power supplyvoltage applied through the cable. That is, there occurs no problem evenif the magnetic field is generated by forming one of the guide rail 7000and the slider 7001 using a magnetic material and forming the otherthereof using a material attracted by the magnetic material. Also, thereoccurs no problem even if both of the guide rail 7000 and the slider7001 are formed using a magnetic material.

[0282] Also, instead of generating the magnetic field using the powersupply voltage applied through the cable, one of the rod 7002 and theslider 7001 may be formed using a magnetic material. Also, both of therod 7002 and the slider 7001 may be formed using a magnetic material.

[0283] By using the means for moving the stage described in thisembodiment, it becomes possible to move the stage along the guide railin a non-contact manner, which saves the necessity to perform periodicalreplacement of a ball due to the wear and tear of the ball and makes iteasy to perform maintenance work. Also, the moving of the stage isperformed in the non-contact manner, so that there hardly occursfriction and it becomes possible to more smoothly perform the moving ofthe stage in comparison with a case where a ball is used.

[0284]FIG. 34C shows a state where an object to be processed 7011 byirradiating laser lights is mounted on a stage 7010 fixed on the slider7001. The moving of the stage is performed more smoothly by means of thestage moving means of this embodiment, which makes it possible to moreuniformly perform the irradiation of the laser lights.

[0285] It is possible to implement this embodiment in combination withthe first to the fourteenth embodiments.

[0286] [Embodiment 16]

[0287] In this embodiment, there will be described an example using anactive vibration removing base.

[0288]FIG. 35A shows a state where the laser apparatus of the presentinvention is mounted on an active vibration removing base. This activevibration removing base includes a board 7100 on which the laserapparatus is actually mounted, a plurality of isolators 7102, a stand7101 that functions as a scaffolding, and a controller 7103.

[0289] The board 7100 is provided on the stand 7101 so that theisolators 7102 are sandwiched therebetween. Each isolator 7102 includesa gimbal piston (air spring) provided with a gimbal mechanism fordetecting a vibration and removing it. Also, the controller 7103controls the operation of each gimbal piston.

[0290] Incidentally, in FIG. 35A, the laser apparatus mounted on theboard 7100 includes four laser oscillation apparatuses 7104. Also,reference numeral 7105 denotes an optical system that is capable ofcondensing laser lights by changing the paths of lights outputted fromthe laser oscillation apparatuses 7104 and processing the shapes oftheir beam spots. Further, the important point concerning the opticalsystem 7105 of the present invention is that it is possible to combinethe beam spots of laser lights outputted from the plurality of laseroscillation apparatuses 7104 by having the beam spots overlap eachother.

[0291] The combined beam spots are irradiated onto a substrate 7106 thatis an object to be processed. The substrate 7106 is mounted on a stage7107. In FIG. 35A, position control means 7108 and 7109 correspond tothe means for controlling the positions of the beam spots on the objectto be processed and the position of the stage 7107 is controlled by theposition control means 7108 and 7109. The position control means 7108performs the control of the position of the stage 7107 in the Xdirection and the position control means 7109 performs the control ofthe position of the stage 7107 in the Y direction.

[0292] A concrete function of the gimbal piston will be described withreference to FIG. 35B. In FIG. 35B, in the portion surrounded by abroken line 7200, there is shown the outline of the construction of thegimbal piston. The gimbal piston 7200 includes a support base 7202 fixedto the stand 7101 and a load disc 7201 fixed to the board 7100. Asupport rod 7204 is fixed to the load disc 7201, which realizes aconstruction where if the load disc 7201 is rocked due to a vibration ofthe board 7100, the support rod 7204 is rocked in a pendulum mannerinside of the support base 7202.

[0293] A displacement sensor 7205 monitors the displacement of the loaddisc 7201 at a position specified by “X” using the support rod 7204.Also, the displacement sensor 7205 monitors the acceleration of thedisplacement of the load disc 7201 at the position specified by “X”using a first acceleration sensor 7206 and monitors the acceleration ofthe displacement of the frame 7101 at a position specified by “X_(o)”using a second acceleration sensor 7207.

[0294] Results of these three monitors are sent to the controller 7103.The controller 7103 obtains the displacement of the board 7100, theacceleration of the displacement, and the speed of the displacement fromthe results of the monitoring by the displacement sensor 7205, the firstacceleration sensor 7206, and the second acceleration sensor 7207, andobtains, from these values, feedback values concerning the displacement,acceleration, and speed in order to suppress the vibration of the board7100. Then, in accordance with the feedback values concerning thedisplacement, acceleration, and speed, a compressed air is given to thegimbal piston 7200 so that an inverse vibration is given to the loaddisc 7201.

[0295] With the construction described above, it becomes possible tocancel out a vibration from the floor, on which the stand 7101 ismounted, and a vibration from the laser apparatus due to the positioncontrol means 7108 and 7109 and the like using a vibration given by thecompressed air and to suppress a vibration of the board 7100.

[0296] It should be noted here that there occurs no problem even if thecontroller 7103 includes a function of studying a vibration given to theboard 7100 and promptly removing a vibration next time when the samevibration is given.

[0297] By suppressing the vibration of the board 7100, it becomespossible to prevent a situation where the alignment of the opticalsystem possessed by the laser apparatus is shifted due to the vibration.In particular, the construction described above is extremely useful inthe case where there is required more precise alignment of the opticalsystem where beam spots are combined using a plurality of laseroscillation apparatuses.

[0298] It is possible to implement this embodiment in combination withthe first to the fifteenth embodiments.

[0299] [Embodiment 17]

[0300] In this embodiment, there will be described the relation between(i) the distance between centers of respective laser beams and (ii) anenergy density in the case where the laser beams are made to overlapeach other.

[0301]FIG. 36 shows the distribution of the energy density of each laserbeam in the center axis direction using a solid line and shows thedistribution of the energy densities of combined laser beams using abroken line. In general, the value of the energy density of a laser beamin the center axis direction is pursuant to the Gaussian distribution.

[0302] As to laser beams before combining, their width in the centeraxis direction, which satisfies an energy density of 1/e² or higher of apeak value, is set at “1” and the distance between respective peaks isreferred to as “X”. Also, as to laser beams after the combining, theincreased amount of a peak value from the average value of valley valuesand the peak value after the combining is referred to as “Y”. Therelation between “X” and “Y” obtained through a simulation is shown inFIG. 37. Note that in FIG. 37, “Y” is expressed on a percentage basis.

[0303] In FIG. 37, an energy difference Y is expressed by Expression 1below that is an approximate expression.

Y=60−293X+340X ²   Expression 1

[0304] (X is larger one of two solutions)

[0305] It can be seen from Expression 1 that in the case where it isdesired to set the energy difference at around 5%, for instance, it issufficient that setting is made so that “X” becomes almost equal to0.584. It is ideal that “Y” becomes equal to zero. In this case,however, the lengths of laser beams are shortened, so that it ispreferable that “X” is determined with consideration given to thebalance with throughput.

[0306] Next, there will be described the allowable range of “Y”. FIG. 38shows the distribution of the output (W) of a YVO₄ laser with respect toits beam width in the center axis direction in the case where the laserbeam has an elliptic shape. The region specified by sloped lines is arange of an output energy that is necessary to obtain favorablecrystallinity and it can be seen that there occurs no problem so long asthe output energy of synthesized laser lights remains within a range offrom 3.5 to 6 W.

[0307] When the maximum value and the minimum value of the output energyof the laser beams after the synthesizing exist close to the insideedges of the output energy range that is necessary to obtain favorablecrystallinity, the energy difference Y, with which it is possible toobtain the favorable crystallinity, becomes the maximum. As a result, inthe case shown in FIG. 38, the energy difference Y becomes ±26.3% and itcan be seen that the favorable crystallinity is obtained if the energydifference “Y” remains within this range.

[0308] It should be noted here that the range of the output energy thatis necessary to obtain the favorable crystallinity changes depending onwhich range of crystallinity is judged as favorable. Also, thedistribution of the output energy changes depending on the shape of alaser beam, so that the allowable range of the energy difference Y isnot limited to the value described above. A designer is required todetermine the range of the output energy that is necessary to obtain thefavorable crystallinity as appropriate and to set the allowable range ofthe energy difference Y from the distribution of the output energy of alaser used.

[0309] It is possible to implement this embodiment in combination withthe first to sixteenth embodiments.

[0310] With the present invention, laser lights are not scanned andirradiated onto the entire surface of a semiconductor film but arescanned so that at least each indispensable portion is crystallized.With the construction described above, it becomes possible to save atime taken to irradiate the laser lights onto each portion to be removedthrough patterning after the crystallization of the semiconductor filmand to significantly shorten a time taken to process one substrate.

What is claimed is:
 1. A production system for a semiconductor devicecomprising: means for forming a marker in a semiconductor film formed onan insulating surface; means for storing information concerning apattern to be formed on the semiconductor film; means for specifying aregion, which will be obtained after patterning of the semiconductorfilm and become an island-like semiconductor film, using the patterninformation with reference to the marker and determining a region of thesemiconductor film to be scanned with a laser light so that at least theregion that will become the island-like semiconductor film is containedin the region to be scanned; a laser oscillation apparatus; an opticalsystem for processing the laser light oscillated from the laseroscillation apparatus; means for controlling a position of a beam spotof the laser light on the semiconductor film so that the processed laserlight is irradiated onto the determined region to be scanned with thelaser light; and means for patterning the semiconductor film irradiatedwith the laser light in accordance with the pattern information.
 2. Aproduction system for a semiconductor device comprising: means forforming a marker in a semiconductor film formed on an insulatingsurface; means for storing information concerning a pattern to be formedon the semiconductor film; means for specifying a region, which will beobtained after patterning of the semiconductor film and become anisland-like semiconductor film, using the pattern information withreference to the marker and determining a region of the semiconductorfilm to be scanned with a laser light so that at least the region thatwill become the island-like semiconductor film is contained in theregion to be scanned; a laser oscillation apparatus; an optical systemfor processing the laser light oscillated from the laser oscillationapparatus; means for controlling a position of a beam spot of the laserlight on the semiconductor film so that the processed laser light isirradiated onto the determined region to be scanned with the laserlight; and means for patterning the semiconductor film irradiated withthe laser light in accordance with the pattern information, wherein whenthe laser light is irradiated, a width of the beam spot of the laserlight on the semiconductor film in a scanning direction is changed.
 3. Aproduction system for a semiconductor device comprising: means forforming a marker by a first laser light in a semiconductor film formedon an insulating surface; means for storing information concerning apattern to be formed on the semiconductor film; means for specifying aregion, which will be obtained after patterning of the semiconductorfilm and become an island-like semiconductor film, using the patterninformation with reference to the marker and determining a region of thesemiconductor film to be scanned with a second laser light so that atleast the region that will become the island-like semiconductor film iscontained in the region to be scanned; a laser oscillation apparatus; anoptical system for processing the second laser light oscillated from thelaser oscillation apparatus; means for controlling a position of a beamspot of the second laser light on the semiconductor film so that theprocessed second laser light is irradiated onto the determined region tobe scanned with the second laser light; and means for patterning thesemiconductor film irradiated with the second laser light in accordancewith the pattern information.
 4. A production system for a semiconductordevice according to any one of claims 1 to 3, wherein the laseroscillation apparatus is a solid laser of continuous oscillation.
 5. Aproduction system for a semiconductor device according to any one ofclaims 1 to 3, wherein the laser oscillation apparatus is at least onekind of laser selected from the group consisting of a YAG laser, a YVO₄laser, a YLF laser, a YAlO₃ laser, a glass laser, a ruby laser, analexandrite laser, a Y₂O₃ laser, and a Ti: sapphire laser of continuousoscillation.
 6. A production system for a semiconductor device accordingto any one of claims 1 to 3, wherein the laser oscillation apparatus isat least one kind of laser selected from the group consisting of anexcimer laser, an Ar laser, and a Kr laser of continuous oscillation. 7.A production system for a semiconductor device according to any one ofclaims 1 to 3, wherein the laser light is second harmonics.
 8. Amanufacturing method for a semiconductor device comprising: outputting aplurality of laser lights from a plurality of laser oscillationapparatuses; forming one beam spot by having beam spots of the pluralityof laser lights overlap each other using an optical system on asemiconductor film; enhancing crystallinity in a region determined bypattern information by scanning the formed beam spot only on the regionof the semiconductor film determined by the pattern information; andforming an island-like semiconductor film having crystallinity bypatterning the region, in which the crystallinity has been enhanced,using the pattern information.
 9. A manufacturing method for asemiconductor device comprising: outputting a plurality of laser lightsfrom a plurality of laser oscillation apparatuses; forming one beam spotby having beam spots of the plurality of laser lights overlap each otherusing an optical system so that centers of the beam spots draw astraight line on a semiconductor film; enhancing crystallinity in aregion determined by pattern information by scanning the formed beamspot only on the region of the semiconductor film determined by thepattern information; and forming an island-like semiconductor filmhaving crystallinity by patterning the region, in which thecrystallinity has been enhanced, using the pattern information.
 10. Amanufacturing method for a semiconductor device according to any one of8 and 9, wherein the laser oscillation apparatus is a solid laser ofcontinuous oscillation.
 11. A manufacturing method for a semiconductordevice according to any one of claims 8 and 9, wherein the laseroscillation apparatus is at least one kind of laser selected from thegroup consisting of a YAG laser, a YVO₄ laser, a YLF laser, a YAlO₃laser, a glass laser, a ruby laser, an alexandrite laser, a Y₂O₃ laser,and a Ti: sapphire laser of continuous oscillation.
 12. A manufacturingmethod for a semiconductor device according to any one of claims 8 and9, wherein the laser oscillation apparatus is at least one kind of laserselected from the group consisting of an excimer laser, an Ar laser, anda Kr laser of continuous oscillation.
 13. A manufacturing method for asemiconductor device according to any one of claims 8 and 9, wherein thelaser light is second harmonics.
 14. A manufacturing method for asemiconductor device according to any one of claims 8 and 9, wherein thenumber of the laser oscillation apparatuses ranges from 2 to
 8. 15. Asemiconductor device that uses a manufacturing method for thesemiconductor device according to any one of claims 8 and
 9. 16. Anelectronic equipment that uses the semiconductor device according to anyone of claims 8 and
 9. 17. A laser apparatus comprising: a plurality oflaser oscillation apparatuses; an optical system that processes aplurality of laser lights outputted from the plurality of laseroscillation apparatuses so that beam spots of the plurality of laserlights partially overlap each other on an object to be processed; meansfor controlling positions of the beam spots of the plurality of laserlights on the object to be processed; and means for controllingoscillation by the plurality of laser oscillation apparatuses andcontrolling the means for controlling the positions of the beam spots ofthe plurality of laser lights so that the beam spots of the plurality oflaser lights scan a specific position of the object to be processeddetermined in accordance with data of pattern information.
 18. A laserapparatus comprising: a plurality of laser oscillation apparatuses; anoptical system that processes a plurality of laser lights outputted fromthe plurality of laser oscillation apparatuses so that beam spots of theplurality of laser lights partially overlap each other on an object tobe processed; means for controlling positions of the beam spots of theplurality of laser lights on the object to be processed; and means forcontrolling oscillation by the plurality of laser oscillationapparatuses and controlling the means for controlling the positions ofthe beam spots of the plurality of laser lights so that the beam spotsof the plurality of laser lights scan a specific position of the objectto be processed determined in accordance with data of patterninformation, wherein the optical system has centers of the beam spots ofthe plurality of laser lights draw a straight line.
 19. A laserapparatus according to any one of claims 17 and 18, wherein the numberof the laser oscillation apparatuses ranges from 2 to
 8. 20. A laserapparatus according to any one of claims 17 and 18, wherein the laseroscillation apparatus is a solid laser of continuous oscillation.
 21. Alaser apparatus according to any one of claims 17 and 18, wherein thelaser oscillation apparatus is at least one kind of laser selected fromthe group consisting of a YAG laser, a YVO₄ laser, a YLF laser, a YAlO₃laser, a glass laser, a ruby laser, an alexandrite laser, a Y₂O₃ laser,and a Ti: sapphire laser of continuous oscillation.
 22. A laserapparatus according to any one of claims 17 and 18, wherein the laseroscillation apparatus is at least one kind of laser selected from thegroup consisting of an excimer laser, an Ar laser, and a Kr laser ofcontinuous oscillation.
 23. A laser apparatus according to any one ofclaims 17 and 18, wherein the laser light is second harmonics.
 24. Alaser irradiation method comprising: outputting a plurality of laserlights from a plurality of laser oscillation apparatuses; forming onebeam spot by having beam spots of the plurality of laser lights overlapeach other using an optical system on a semiconductor film; scanning theformed beam spot only on the region of the semiconductor film determinedby the pattern information.
 25. A laser irradiation method comprising:outputting a plurality of laser lights from a plurality of laseroscillation apparatuses; forming one beam spot by having beam spots ofthe plurality of laser lights overlap each other using an optical systemso that centers of the beam spots draw a straight line on asemiconductor film; and scanning the formed beam spot only on the regionof the semiconductor film determined by the pattern information.
 26. Alaser irradiation method according to any one of claim 24 and 25,wherein the laser oscillation apparatus is a solid laser of continuousoscillation.
 27. A laser irradiation method according to any one ofclaims 24 and 25, wherein the laser oscillation apparatus is at leastone kind of laser selected from the group consisting of a YAG laser, aYVO₄ laser, a YLF laser, a YAlO₃ laser, a glass laser, a ruby laser, analexandrite laser, a Y₂O₃ laser, and a Ti: sapphire laser of continuousoscillation.
 28. A laser irradiation method according to any one ofclaims 24 and 25, wherein the laser oscillation apparatus is at leastone kind of laser selected from the group consisting of an excimerlaser, an Ar laser, and a Kr laser of continuous oscillation.
 29. Alaser irradiation method according to any one of claims 24 and 25,wherein the laser light is second harmonics.
 30. A laser irradiationmethod according to any one of claims 24 and 25, wherein the number ofthe laser oscillation apparatuses ranges from 2 to 8.